src/Pure/term.ML
author wenzelm
Thu Oct 01 23:27:05 2009 +0200 (2009-10-01)
changeset 32843 c8f5a7c8353f
parent 32784 1a5dde5079ac
child 33063 4d462963a7db
permissions -rw-r--r--
moved cache_conv to src/Pure/conv.ML, use Thm.cterm_cache;
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(*  Title:      Pure/term.ML
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    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
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    Author:     Makarius
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Simply typed lambda-calculus: types, terms, and basic operations.
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*)
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infix 9 $;
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infixr 5 -->;
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infixr --->;
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infix aconv;
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signature BASIC_TERM =
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sig
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  eqtype indexname
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  eqtype class
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  eqtype sort
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  eqtype arity
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  datatype typ =
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    Type  of string * typ list |
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    TFree of string * sort |
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    TVar  of indexname * sort
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  datatype term =
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    Const of string * typ |
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    Free of string * typ |
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    Var of indexname * typ |
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    Bound of int |
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    Abs of string * typ * term |
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    $ of term * term
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  exception TYPE of string * typ list * term list
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  exception TERM of string * term list
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  val dummyS: sort
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  val dummyT: typ
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  val no_dummyT: typ -> typ
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  val --> : typ * typ -> typ
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  val ---> : typ list * typ -> typ
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  val dest_Type: typ -> string * typ list
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  val dest_TVar: typ -> indexname * sort
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  val dest_TFree: typ -> string * sort
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  val is_Bound: term -> bool
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  val is_Const: term -> bool
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  val is_Free: term -> bool
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  val is_Var: term -> bool
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  val is_TVar: typ -> bool
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  val dest_Const: term -> string * typ
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  val dest_Free: term -> string * typ
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  val dest_Var: term -> indexname * typ
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  val domain_type: typ -> typ
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  val range_type: typ -> typ
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  val binder_types: typ -> typ list
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  val body_type: typ -> typ
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  val strip_type: typ -> typ list * typ
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  val type_of1: typ list * term -> typ
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  val type_of: term -> typ
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  val fastype_of1: typ list * term -> typ
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  val fastype_of: term -> typ
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  val list_abs: (string * typ) list * term -> term
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  val strip_abs: term -> (string * typ) list * term
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  val strip_abs_body: term -> term
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  val strip_abs_vars: term -> (string * typ) list
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  val strip_qnt_body: string -> term -> term
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  val strip_qnt_vars: string -> term -> (string * typ) list
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  val list_comb: term * term list -> term
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  val strip_comb: term -> term * term list
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  val head_of: term -> term
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  val size_of_term: term -> int
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  val size_of_typ: typ -> int
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  val map_atyps: (typ -> typ) -> typ -> typ
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  val map_aterms: (term -> term) -> term -> term
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  val map_type_tvar: (indexname * sort -> typ) -> typ -> typ
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  val map_type_tfree: (string * sort -> typ) -> typ -> typ
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  val map_types: (typ -> typ) -> term -> term
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  val fold_atyps: (typ -> 'a -> 'a) -> typ -> 'a -> 'a
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  val fold_aterms: (term -> 'a -> 'a) -> term -> 'a -> 'a
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  val fold_term_types: (term -> typ -> 'a -> 'a) -> term -> 'a -> 'a
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  val fold_types: (typ -> 'a -> 'a) -> term -> 'a -> 'a
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  val burrow_types: (typ list -> typ list) -> term list -> term list
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  val aconv: term * term -> bool
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  val propT: typ
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  val strip_all_body: term -> term
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  val strip_all_vars: term -> (string * typ) list
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  val incr_bv: int * int * term -> term
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  val incr_boundvars: int -> term -> term
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  val add_loose_bnos: term * int * int list -> int list
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  val loose_bnos: term -> int list
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  val loose_bvar: term * int -> bool
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  val loose_bvar1: term * int -> bool
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  val subst_bounds: term list * term -> term
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  val subst_bound: term * term -> term
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  val betapply: term * term -> term
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  val betapplys: term * term list -> term
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  val subst_free: (term * term) list -> term -> term
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  val abstract_over: term * term -> term
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  val lambda: term -> term -> term
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  val absfree: string * typ * term -> term
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  val absdummy: typ * term -> term
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  val list_abs_free: (string * typ) list * term -> term
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  val list_all_free: (string * typ) list * term -> term
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  val list_all: (string * typ) list * term -> term
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  val subst_atomic: (term * term) list -> term -> term
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  val typ_subst_atomic: (typ * typ) list -> typ -> typ
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  val subst_atomic_types: (typ * typ) list -> term -> term
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  val typ_subst_TVars: (indexname * typ) list -> typ -> typ
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  val subst_TVars: (indexname * typ) list -> term -> term
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  val subst_Vars: (indexname * term) list -> term -> term
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  val subst_vars: (indexname * typ) list * (indexname * term) list -> term -> term
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  val is_first_order: string list -> term -> bool
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  val maxidx_of_typ: typ -> int
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  val maxidx_of_typs: typ list -> int
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  val maxidx_of_term: term -> int
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  val exists_subtype: (typ -> bool) -> typ -> bool
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  val exists_type: (typ -> bool) -> term -> bool
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  val exists_subterm: (term -> bool) -> term -> bool
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  val exists_Const: (string * typ -> bool) -> term -> bool
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  val show_question_marks: bool Unsynchronized.ref
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end;
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signature TERM =
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sig
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  include BASIC_TERM
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  val aT: sort -> typ
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  val itselfT: typ -> typ
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  val a_itselfT: typ
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  val all: typ -> term
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  val argument_type_of: term -> int -> typ
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  val add_tvar_namesT: typ -> indexname list -> indexname list
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  val add_tvar_names: term -> indexname list -> indexname list
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  val add_tvarsT: typ -> (indexname * sort) list -> (indexname * sort) list
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  val add_tvars: term -> (indexname * sort) list -> (indexname * sort) list
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  val add_var_names: term -> indexname list -> indexname list
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  val add_vars: term -> (indexname * typ) list -> (indexname * typ) list
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  val add_tfree_namesT: typ -> string list -> string list
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  val add_tfree_names: term -> string list -> string list
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  val add_tfreesT: typ -> (string * sort) list -> (string * sort) list
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  val add_tfrees: term -> (string * sort) list -> (string * sort) list
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  val add_free_names: term -> string list -> string list
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  val add_frees: term -> (string * typ) list -> (string * typ) list
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  val add_const_names: term -> string list -> string list
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  val add_consts: term -> (string * typ) list -> (string * typ) list
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  val hidden_polymorphism: term -> (indexname * sort) list
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  val declare_typ_names: typ -> Name.context -> Name.context
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  val declare_term_names: term -> Name.context -> Name.context
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  val declare_term_frees: term -> Name.context -> Name.context
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  val variant_frees: term -> (string * 'a) list -> (string * 'a) list
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  val rename_wrt_term: term -> (string * 'a) list -> (string * 'a) list
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  val eq_ix: indexname * indexname -> bool
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  val eq_tvar: (indexname * sort) * (indexname * sort) -> bool
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  val eq_var: (indexname * typ) * (indexname * typ) -> bool
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  val could_unify: term * term -> bool
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  val strip_abs_eta: int -> term -> (string * typ) list * term
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  val match_bvars: (term * term) * (string * string) list -> (string * string) list
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  val map_abs_vars: (string -> string) -> term -> term
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  val rename_abs: term -> term -> term -> term option
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  val lambda_name: string * term -> term -> term
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  val close_schematic_term: term -> term
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  val maxidx_typ: typ -> int -> int
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  val maxidx_typs: typ list -> int -> int
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  val maxidx_term: term -> int -> int
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  val has_abs: term -> bool
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  val dest_abs: string * typ * term -> string * term
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  val dummy_patternN: string
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  val dummy_pattern: typ -> term
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  val is_dummy_pattern: term -> bool
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  val free_dummy_patterns: term -> Name.context -> term * Name.context
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  val no_dummy_patterns: term -> term
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  val replace_dummy_patterns: term -> int -> term * int
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  val is_replaced_dummy_pattern: indexname -> bool
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  val show_dummy_patterns: term -> term
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  val string_of_vname: indexname -> string
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  val string_of_vname': indexname -> string
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end;
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structure Term: TERM =
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struct
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(*Indexnames can be quickly renamed by adding an offset to the integer part,
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  for resolution.*)
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type indexname = string * int;
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(* Types are classified by sorts. *)
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type class = string;
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type sort  = class list;
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type arity = string * sort list * sort;
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(* The sorts attached to TFrees and TVars specify the sort of that variable *)
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datatype typ = Type  of string * typ list
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             | TFree of string * sort
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             | TVar  of indexname * sort;
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(*Terms.  Bound variables are indicated by depth number.
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  Free variables, (scheme) variables and constants have names.
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  An term is "closed" if every bound variable of level "lev"
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  is enclosed by at least "lev" abstractions.
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  It is possible to create meaningless terms containing loose bound vars
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  or type mismatches.  But such terms are not allowed in rules. *)
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datatype term =
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    Const of string * typ
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  | Free  of string * typ
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  | Var   of indexname * typ
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  | Bound of int
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  | Abs   of string*typ*term
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  | op $  of term*term;
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(*Errors involving type mismatches*)
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exception TYPE of string * typ list * term list;
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(*Errors errors involving terms*)
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exception TERM of string * term list;
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(*Note variable naming conventions!
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    a,b,c: string
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    f,g,h: functions (including terms of function type)
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    i,j,m,n: int
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    t,u: term
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    v,w: indexnames
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    x,y: any
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    A,B,C: term (denoting formulae)
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    T,U: typ
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*)
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(** Types **)
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(*dummies for type-inference etc.*)
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val dummyS = [""];
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val dummyT = Type ("dummy", []);
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fun no_dummyT typ =
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  let
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    fun check (T as Type ("dummy", _)) =
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          raise TYPE ("Illegal occurrence of '_' dummy type", [T], [])
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      | check (Type (_, Ts)) = List.app check Ts
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      | check _ = ();
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  in check typ; typ end;
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fun S --> T = Type("fun",[S,T]);
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(*handy for multiple args: [T1,...,Tn]--->T  gives  T1-->(T2--> ... -->T)*)
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val op ---> = Library.foldr (op -->);
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fun dest_Type (Type x) = x
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  | dest_Type T = raise TYPE ("dest_Type", [T], []);
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fun dest_TVar (TVar x) = x
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  | dest_TVar T = raise TYPE ("dest_TVar", [T], []);
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fun dest_TFree (TFree x) = x
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  | dest_TFree T = raise TYPE ("dest_TFree", [T], []);
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(** Discriminators **)
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fun is_Bound (Bound _) = true
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  | is_Bound _         = false;
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fun is_Const (Const _) = true
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  | is_Const _ = false;
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fun is_Free (Free _) = true
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  | is_Free _ = false;
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fun is_Var (Var _) = true
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  | is_Var _ = false;
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fun is_TVar (TVar _) = true
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  | is_TVar _ = false;
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(** Destructors **)
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fun dest_Const (Const x) =  x
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  | dest_Const t = raise TERM("dest_Const", [t]);
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fun dest_Free (Free x) =  x
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  | dest_Free t = raise TERM("dest_Free", [t]);
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fun dest_Var (Var x) =  x
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  | dest_Var t = raise TERM("dest_Var", [t]);
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fun domain_type (Type("fun", [T,_])) = T
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and range_type  (Type("fun", [_,T])) = T;
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(* maps  [T1,...,Tn]--->T  to the list  [T1,T2,...,Tn]*)
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fun binder_types (Type("fun",[S,T])) = S :: binder_types T
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  | binder_types _   =  [];
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(* maps  [T1,...,Tn]--->T  to T*)
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fun body_type (Type("fun",[S,T])) = body_type T
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  | body_type T   =  T;
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(* maps  [T1,...,Tn]--->T  to   ([T1,T2,...,Tn], T)  *)
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fun strip_type T : typ list * typ =
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  (binder_types T, body_type T);
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(*Compute the type of the term, checking that combinations are well-typed
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  Ts = [T0,T1,...] holds types of bound variables 0, 1, ...*)
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fun type_of1 (Ts, Const (_,T)) = T
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  | type_of1 (Ts, Free  (_,T)) = T
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  | type_of1 (Ts, Bound i) = (nth Ts i
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        handle Subscript => raise TYPE("type_of: bound variable", [], [Bound i]))
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  | type_of1 (Ts, Var (_,T)) = T
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  | type_of1 (Ts, Abs (_,T,body)) = T --> type_of1(T::Ts, body)
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  | type_of1 (Ts, f$u) =
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      let val U = type_of1(Ts,u)
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          and T = type_of1(Ts,f)
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      in case T of
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            Type("fun",[T1,T2]) =>
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              if T1=U then T2  else raise TYPE
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                    ("type_of: type mismatch in application", [T1,U], [f$u])
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          | _ => raise TYPE
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                    ("type_of: function type is expected in application",
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                     [T,U], [f$u])
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      end;
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fun type_of t : typ = type_of1 ([],t);
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(*Determines the type of a term, with minimal checking*)
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fun fastype_of1 (Ts, f$u) =
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    (case fastype_of1 (Ts,f) of
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        Type("fun",[_,T]) => T
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        | _ => raise TERM("fastype_of: expected function type", [f$u]))
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  | fastype_of1 (_, Const (_,T)) = T
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  | fastype_of1 (_, Free (_,T)) = T
wenzelm@30146
   326
  | fastype_of1 (Ts, Bound i) = (nth Ts i
skalberg@15570
   327
         handle Subscript => raise TERM("fastype_of: Bound", [Bound i]))
wenzelm@13000
   328
  | fastype_of1 (_, Var (_,T)) = T
lcp@61
   329
  | fastype_of1 (Ts, Abs (_,T,u)) = T --> fastype_of1 (T::Ts, u);
lcp@61
   330
lcp@61
   331
fun fastype_of t : typ = fastype_of1 ([],t);
clasohm@0
   332
wenzelm@16678
   333
(*Determine the argument type of a function*)
wenzelm@22908
   334
fun argument_type_of tm k =
wenzelm@16678
   335
  let
wenzelm@16678
   336
    fun argT i (Type ("fun", [T, U])) = if i = 0 then T else argT (i - 1) U
wenzelm@16678
   337
      | argT _ T = raise TYPE ("argument_type_of", [T], []);
wenzelm@16678
   338
wenzelm@16678
   339
    fun arg 0 _ (Abs (_, T, _)) = T
wenzelm@16678
   340
      | arg i Ts (Abs (_, T, t)) = arg (i - 1) (T :: Ts) t
wenzelm@16678
   341
      | arg i Ts (t $ _) = arg (i + 1) Ts t
wenzelm@16678
   342
      | arg i Ts a = argT i (fastype_of1 (Ts, a));
wenzelm@22908
   343
  in arg k [] tm end;
wenzelm@16678
   344
clasohm@0
   345
wenzelm@19473
   346
val list_abs = uncurry (fold_rev (fn (x, T) => fn t => Abs (x, T, t)));
wenzelm@10806
   347
haftmann@18927
   348
fun strip_abs (Abs (a, T, t)) =
haftmann@18927
   349
      let val (a', t') = strip_abs t
haftmann@18927
   350
      in ((a, T) :: a', t') end
haftmann@18927
   351
  | strip_abs t = ([], t);
haftmann@18927
   352
clasohm@0
   353
(* maps  (x1,...,xn)t   to   t  *)
wenzelm@13000
   354
fun strip_abs_body (Abs(_,_,t))  =  strip_abs_body t
clasohm@0
   355
  | strip_abs_body u  =  u;
clasohm@0
   356
clasohm@0
   357
(* maps  (x1,...,xn)t   to   [x1, ..., xn]  *)
wenzelm@13000
   358
fun strip_abs_vars (Abs(a,T,t))  =  (a,T) :: strip_abs_vars t
clasohm@0
   359
  | strip_abs_vars u  =  [] : (string*typ) list;
clasohm@0
   360
clasohm@0
   361
clasohm@0
   362
fun strip_qnt_body qnt =
clasohm@0
   363
let fun strip(tm as Const(c,_)$Abs(_,_,t)) = if c=qnt then strip t else tm
clasohm@0
   364
      | strip t = t
clasohm@0
   365
in strip end;
clasohm@0
   366
clasohm@0
   367
fun strip_qnt_vars qnt =
clasohm@0
   368
let fun strip(Const(c,_)$Abs(a,T,t)) = if c=qnt then (a,T)::strip t else []
clasohm@0
   369
      | strip t  =  [] : (string*typ) list
clasohm@0
   370
in strip end;
clasohm@0
   371
clasohm@0
   372
clasohm@0
   373
(* maps   (f, [t1,...,tn])  to  f(t1,...,tn) *)
skalberg@15570
   374
val list_comb : term * term list -> term = Library.foldl (op $);
clasohm@0
   375
clasohm@0
   376
clasohm@0
   377
(* maps   f(t1,...,tn)  to  (f, [t1,...,tn]) ; naturally tail-recursive*)
wenzelm@13000
   378
fun strip_comb u : term * term list =
clasohm@0
   379
    let fun stripc (f$t, ts) = stripc (f, t::ts)
wenzelm@13000
   380
        |   stripc  x =  x
clasohm@0
   381
    in  stripc(u,[])  end;
clasohm@0
   382
clasohm@0
   383
clasohm@0
   384
(* maps   f(t1,...,tn)  to  f , which is never a combination *)
clasohm@0
   385
fun head_of (f$t) = head_of f
clasohm@0
   386
  | head_of u = u;
clasohm@0
   387
wenzelm@16599
   388
(*number of atoms and abstractions in a term*)
wenzelm@16599
   389
fun size_of_term tm =
wenzelm@16599
   390
  let
wenzelm@30144
   391
    fun add_size (t $ u) n = add_size t (add_size u n)
wenzelm@30144
   392
      | add_size (Abs (_ ,_, t)) n = add_size t (n + 1)
wenzelm@30144
   393
      | add_size _ n = n + 1;
wenzelm@30144
   394
  in add_size tm 0 end;
clasohm@0
   395
wenzelm@30144
   396
(*number of atoms and constructors in a type*)
kleing@29882
   397
fun size_of_typ ty =
kleing@29882
   398
  let
wenzelm@30144
   399
    fun add_size (Type (_, tys)) n = fold add_size tys (n + 1)
wenzelm@30144
   400
      | add_size _ n = n + 1;
wenzelm@30144
   401
  in add_size ty 0 end;
kleing@29882
   402
haftmann@18847
   403
fun map_atyps f (Type (a, Ts)) = Type (a, map (map_atyps f) Ts)
haftmann@18976
   404
  | map_atyps f T = f T;
haftmann@18847
   405
haftmann@18847
   406
fun map_aterms f (t $ u) = map_aterms f t $ map_aterms f u
haftmann@18847
   407
  | map_aterms f (Abs (a, T, t)) = Abs (a, T, map_aterms f t)
haftmann@18847
   408
  | map_aterms f t = f t;
haftmann@18847
   409
wenzelm@18981
   410
fun map_type_tvar f = map_atyps (fn TVar x => f x | T => T);
wenzelm@18981
   411
fun map_type_tfree f = map_atyps (fn TFree x => f x | T => T);
nipkow@949
   412
wenzelm@20548
   413
fun map_types f =
wenzelm@16678
   414
  let
wenzelm@16678
   415
    fun map_aux (Const (a, T)) = Const (a, f T)
wenzelm@16678
   416
      | map_aux (Free (a, T)) = Free (a, f T)
wenzelm@16678
   417
      | map_aux (Var (v, T)) = Var (v, f T)
wenzelm@16678
   418
      | map_aux (t as Bound _)  = t
wenzelm@16678
   419
      | map_aux (Abs (a, T, t)) = Abs (a, f T, map_aux t)
wenzelm@16678
   420
      | map_aux (t $ u) = map_aux t $ map_aux u;
wenzelm@16678
   421
  in map_aux end;
clasohm@0
   422
clasohm@0
   423
wenzelm@16943
   424
(* fold types and terms *)
wenzelm@16943
   425
wenzelm@16943
   426
fun fold_atyps f (Type (_, Ts)) = fold (fold_atyps f) Ts
wenzelm@16943
   427
  | fold_atyps f T = f T;
wenzelm@16943
   428
wenzelm@16943
   429
fun fold_aterms f (t $ u) = fold_aterms f t #> fold_aterms f u
wenzelm@16943
   430
  | fold_aterms f (Abs (_, _, t)) = fold_aterms f t
wenzelm@16943
   431
  | fold_aterms f a = f a;
wenzelm@16943
   432
wenzelm@16943
   433
fun fold_term_types f (t as Const (_, T)) = f t T
wenzelm@16943
   434
  | fold_term_types f (t as Free (_, T)) = f t T
wenzelm@16943
   435
  | fold_term_types f (t as Var (_, T)) = f t T
wenzelm@16943
   436
  | fold_term_types f (Bound _) = I
wenzelm@16943
   437
  | fold_term_types f (t as Abs (_, T, b)) = f t T #> fold_term_types f b
wenzelm@16943
   438
  | fold_term_types f (t $ u) = fold_term_types f t #> fold_term_types f u;
wenzelm@16943
   439
wenzelm@16943
   440
fun fold_types f = fold_term_types (K f);
wenzelm@16943
   441
wenzelm@24483
   442
fun replace_types (Const (c, _)) (T :: Ts) = (Const (c, T), Ts)
wenzelm@24483
   443
  | replace_types (Free (x, _)) (T :: Ts) = (Free (x, T), Ts)
wenzelm@24483
   444
  | replace_types (Var (xi, _)) (T :: Ts) = (Var (xi, T), Ts)
wenzelm@24483
   445
  | replace_types (Bound i) Ts = (Bound i, Ts)
wenzelm@24483
   446
  | replace_types (Abs (x, _, b)) (T :: Ts) =
wenzelm@24483
   447
      let val (b', Ts') = replace_types b Ts
wenzelm@24483
   448
      in (Abs (x, T, b'), Ts') end
wenzelm@24483
   449
  | replace_types (t $ u) Ts =
wenzelm@24483
   450
      let
wenzelm@24483
   451
        val (t', Ts') = replace_types t Ts;
wenzelm@24483
   452
        val (u', Ts'') = replace_types u Ts';
wenzelm@24483
   453
      in (t' $ u', Ts'') end;
wenzelm@24483
   454
wenzelm@24483
   455
fun burrow_types f ts =
wenzelm@24483
   456
  let
wenzelm@24483
   457
    val Ts = rev (fold (fold_types cons) ts []);
wenzelm@24483
   458
    val Ts' = f Ts;
wenzelm@24483
   459
    val (ts', []) = fold_map replace_types ts Ts';
wenzelm@24483
   460
  in ts' end;
wenzelm@24483
   461
wenzelm@16943
   462
(*collect variables*)
wenzelm@29257
   463
val add_tvar_namesT = fold_atyps (fn TVar (xi, _) => insert (op =) xi | _ => I);
wenzelm@29257
   464
val add_tvar_names = fold_types add_tvar_namesT;
wenzelm@16943
   465
val add_tvarsT = fold_atyps (fn TVar v => insert (op =) v | _ => I);
wenzelm@16943
   466
val add_tvars = fold_types add_tvarsT;
wenzelm@29257
   467
val add_var_names = fold_aterms (fn Var (xi, _) => insert (op =) xi | _ => I);
wenzelm@16943
   468
val add_vars = fold_aterms (fn Var v => insert (op =) v | _ => I);
wenzelm@29257
   469
val add_tfree_namesT = fold_atyps (fn TFree (xi, _) => insert (op =) xi | _ => I);
wenzelm@29257
   470
val add_tfree_names = fold_types add_tfree_namesT;
wenzelm@16943
   471
val add_tfreesT = fold_atyps (fn TFree v => insert (op =) v | _ => I);
wenzelm@16943
   472
val add_tfrees = fold_types add_tfreesT;
wenzelm@29257
   473
val add_free_names = fold_aterms (fn Free (x, _) => insert (op =) x | _ => I);
wenzelm@16943
   474
val add_frees = fold_aterms (fn Free v => insert (op =) v | _ => I);
wenzelm@29286
   475
val add_const_names = fold_aterms (fn Const (c, _) => insert (op =) c | _ => I);
wenzelm@29286
   476
val add_consts = fold_aterms (fn Const c => insert (op =) c | _ => I);
wenzelm@16943
   477
wenzelm@25050
   478
(*extra type variables in a term, not covered by its type*)
wenzelm@25050
   479
fun hidden_polymorphism t =
wenzelm@21682
   480
  let
wenzelm@25050
   481
    val T = fastype_of t;
wenzelm@21682
   482
    val tvarsT = add_tvarsT T [];
wenzelm@21682
   483
    val extra_tvars = fold_types (fold_atyps
wenzelm@21682
   484
      (fn TVar v => if member (op =) tvarsT v then I else insert (op =) v | _ => I)) t [];
wenzelm@21682
   485
  in extra_tvars end;
wenzelm@21682
   486
wenzelm@16943
   487
wenzelm@29278
   488
(* renaming variables *)
wenzelm@29278
   489
wenzelm@29278
   490
val declare_typ_names = fold_atyps (fn TFree (a, _) => Name.declare a | _ => I);
wenzelm@29278
   491
wenzelm@29278
   492
fun declare_term_names tm =
wenzelm@29278
   493
  fold_aterms
wenzelm@30364
   494
    (fn Const (a, _) => Name.declare (Long_Name.base_name a)
wenzelm@29278
   495
      | Free (a, _) => Name.declare a
wenzelm@29278
   496
      | _ => I) tm #>
wenzelm@29278
   497
  fold_types declare_typ_names tm;
wenzelm@29278
   498
wenzelm@29278
   499
val declare_term_frees = fold_aterms (fn Free (x, _) => Name.declare x | _ => I);
wenzelm@29278
   500
wenzelm@29278
   501
fun variant_frees t frees =
wenzelm@29278
   502
  fst (Name.variants (map fst frees) (declare_term_names t Name.context)) ~~ map snd frees;
wenzelm@29278
   503
wenzelm@29278
   504
fun rename_wrt_term t frees = rev (variant_frees t frees);  (*reversed result!*)
wenzelm@29278
   505
wenzelm@29278
   506
wenzelm@25050
   507
wenzelm@29269
   508
(** Comparing terms **)
wenzelm@29269
   509
wenzelm@29269
   510
(* variables *)
wenzelm@29269
   511
wenzelm@29269
   512
fun eq_ix ((x, i): indexname, (y, j)) = i = j andalso x = y;
wenzelm@16537
   513
wenzelm@29269
   514
fun eq_tvar ((xi, S: sort), (xi', S')) = eq_ix (xi, xi') andalso S = S';
wenzelm@29269
   515
fun eq_var ((xi, T: typ), (xi', T')) = eq_ix (xi, xi') andalso T = T';
wenzelm@29269
   516
wenzelm@29269
   517
wenzelm@29269
   518
(* alpha equivalence *)
wenzelm@20511
   519
wenzelm@20511
   520
fun tm1 aconv tm2 =
wenzelm@20511
   521
  pointer_eq (tm1, tm2) orelse
wenzelm@20511
   522
    (case (tm1, tm2) of
wenzelm@20511
   523
      (t1 $ u1, t2 $ u2) => t1 aconv t2 andalso u1 aconv u2
wenzelm@20511
   524
    | (Abs (_, T1, t1), Abs (_, T2, t2)) => t1 aconv t2 andalso T1 = T2
wenzelm@20511
   525
    | (a1, a2) => a1 = a2);
wenzelm@20511
   526
wenzelm@20511
   527
wenzelm@29269
   528
(*A fast unification filter: true unless the two terms cannot be unified.
wenzelm@29269
   529
  Terms must be NORMAL.  Treats all Vars as distinct. *)
wenzelm@29269
   530
fun could_unify (t, u) =
wenzelm@29269
   531
  let
wenzelm@29269
   532
    fun matchrands (f $ t) (g $ u) = could_unify (t, u) andalso matchrands f g
wenzelm@29269
   533
      | matchrands _ _ = true;
wenzelm@29269
   534
  in
wenzelm@29269
   535
    case (head_of t, head_of u) of
wenzelm@29269
   536
      (_, Var _) => true
wenzelm@29269
   537
    | (Var _, _) => true
wenzelm@29269
   538
    | (Const (a, _), Const (b, _)) => a = b andalso matchrands t u
wenzelm@29269
   539
    | (Free (a, _), Free (b, _)) => a = b andalso matchrands t u
wenzelm@29269
   540
    | (Bound i, Bound j) => i = j andalso matchrands t u
wenzelm@29269
   541
    | (Abs _, _) => true   (*because of possible eta equality*)
wenzelm@29269
   542
    | (_, Abs _) => true
wenzelm@29269
   543
    | _ => false
wenzelm@29269
   544
  end;
wenzelm@16678
   545
nipkow@16570
   546
wenzelm@16537
   547
clasohm@0
   548
(** Connectives of higher order logic **)
clasohm@0
   549
wenzelm@24850
   550
fun aT S = TFree (Name.aT, S);
wenzelm@19394
   551
wenzelm@375
   552
fun itselfT ty = Type ("itself", [ty]);
wenzelm@24850
   553
val a_itselfT = itselfT (TFree (Name.aT, []));
wenzelm@375
   554
clasohm@0
   555
val propT : typ = Type("prop",[]);
clasohm@0
   556
clasohm@0
   557
fun all T = Const("all", (T-->propT)-->propT);
clasohm@0
   558
clasohm@0
   559
(* maps  !!x1...xn. t   to   t  *)
wenzelm@13000
   560
fun strip_all_body (Const("all",_)$Abs(_,_,t))  =  strip_all_body t
clasohm@0
   561
  | strip_all_body t  =  t;
clasohm@0
   562
clasohm@0
   563
(* maps  !!x1...xn. t   to   [x1, ..., xn]  *)
clasohm@0
   564
fun strip_all_vars (Const("all",_)$Abs(a,T,t))  =
wenzelm@13000
   565
                (a,T) :: strip_all_vars t
clasohm@0
   566
  | strip_all_vars t  =  [] : (string*typ) list;
clasohm@0
   567
clasohm@0
   568
(*increments a term's non-local bound variables
clasohm@0
   569
  required when moving a term within abstractions
clasohm@0
   570
     inc is  increment for bound variables
clasohm@0
   571
     lev is  level at which a bound variable is considered 'loose'*)
wenzelm@13000
   572
fun incr_bv (inc, lev, u as Bound i) = if i>=lev then Bound(i+inc) else u
clasohm@0
   573
  | incr_bv (inc, lev, Abs(a,T,body)) =
wenzelm@9536
   574
        Abs(a, T, incr_bv(inc,lev+1,body))
wenzelm@13000
   575
  | incr_bv (inc, lev, f$t) =
clasohm@0
   576
      incr_bv(inc,lev,f) $ incr_bv(inc,lev,t)
clasohm@0
   577
  | incr_bv (inc, lev, u) = u;
clasohm@0
   578
clasohm@0
   579
fun incr_boundvars  0  t = t
clasohm@0
   580
  | incr_boundvars inc t = incr_bv(inc,0,t);
clasohm@0
   581
wenzelm@12981
   582
(*Scan a pair of terms; while they are similar,
wenzelm@12981
   583
  accumulate corresponding bound vars in "al"*)
wenzelm@12981
   584
fun match_bvs(Abs(x,_,s),Abs(y,_,t), al) =
wenzelm@12981
   585
      match_bvs(s, t, if x="" orelse y="" then al
wenzelm@12981
   586
                                          else (x,y)::al)
wenzelm@12981
   587
  | match_bvs(f$s, g$t, al) = match_bvs(f,g,match_bvs(s,t,al))
wenzelm@12981
   588
  | match_bvs(_,_,al) = al;
wenzelm@12981
   589
wenzelm@12981
   590
(* strip abstractions created by parameters *)
wenzelm@12981
   591
fun match_bvars((s,t),al) = match_bvs(strip_abs_body s, strip_abs_body t, al);
wenzelm@12981
   592
haftmann@22031
   593
fun map_abs_vars f (t $ u) = map_abs_vars f t $ map_abs_vars f u
haftmann@22031
   594
  | map_abs_vars f (Abs (a, T, t)) = Abs (f a, T, map_abs_vars f t)
haftmann@22031
   595
  | map_abs_vars f t = t;
haftmann@22031
   596
wenzelm@12981
   597
fun rename_abs pat obj t =
wenzelm@12981
   598
  let
wenzelm@12981
   599
    val ren = match_bvs (pat, obj, []);
wenzelm@12981
   600
    fun ren_abs (Abs (x, T, b)) =
wenzelm@18942
   601
          Abs (the_default x (AList.lookup (op =) ren x), T, ren_abs b)
wenzelm@12981
   602
      | ren_abs (f $ t) = ren_abs f $ ren_abs t
wenzelm@12981
   603
      | ren_abs t = t
skalberg@15531
   604
  in if null ren then NONE else SOME (ren_abs t) end;
clasohm@0
   605
clasohm@0
   606
(*Accumulate all 'loose' bound vars referring to level 'lev' or beyond.
clasohm@0
   607
   (Bound 0) is loose at level 0 *)
wenzelm@13000
   608
fun add_loose_bnos (Bound i, lev, js) =
haftmann@20854
   609
        if i<lev then js else insert (op =) (i - lev) js
clasohm@0
   610
  | add_loose_bnos (Abs (_,_,t), lev, js) = add_loose_bnos (t, lev+1, js)
clasohm@0
   611
  | add_loose_bnos (f$t, lev, js) =
wenzelm@13000
   612
        add_loose_bnos (f, lev, add_loose_bnos (t, lev, js))
clasohm@0
   613
  | add_loose_bnos (_, _, js) = js;
clasohm@0
   614
clasohm@0
   615
fun loose_bnos t = add_loose_bnos (t, 0, []);
clasohm@0
   616
clasohm@0
   617
(* loose_bvar(t,k) iff t contains a 'loose' bound variable referring to
clasohm@0
   618
   level k or beyond. *)
clasohm@0
   619
fun loose_bvar(Bound i,k) = i >= k
clasohm@0
   620
  | loose_bvar(f$t, k) = loose_bvar(f,k) orelse loose_bvar(t,k)
clasohm@0
   621
  | loose_bvar(Abs(_,_,t),k) = loose_bvar(t,k+1)
clasohm@0
   622
  | loose_bvar _ = false;
clasohm@0
   623
nipkow@2792
   624
fun loose_bvar1(Bound i,k) = i = k
nipkow@2792
   625
  | loose_bvar1(f$t, k) = loose_bvar1(f,k) orelse loose_bvar1(t,k)
nipkow@2792
   626
  | loose_bvar1(Abs(_,_,t),k) = loose_bvar1(t,k+1)
nipkow@2792
   627
  | loose_bvar1 _ = false;
clasohm@0
   628
clasohm@0
   629
(*Substitute arguments for loose bound variables.
clasohm@0
   630
  Beta-reduction of arg(n-1)...arg0 into t replacing (Bound i) with (argi).
wenzelm@4626
   631
  Note that for ((%x y. c) a b), the bound vars in c are x=1 and y=0
wenzelm@9536
   632
        and the appropriate call is  subst_bounds([b,a], c) .
clasohm@0
   633
  Loose bound variables >=n are reduced by "n" to
clasohm@0
   634
     compensate for the disappearance of lambdas.
clasohm@0
   635
*)
wenzelm@13000
   636
fun subst_bounds (args: term list, t) : term =
wenzelm@19065
   637
  let
wenzelm@19065
   638
    val n = length args;
wenzelm@19065
   639
    fun subst (t as Bound i, lev) =
wenzelm@32020
   640
         (if i < lev then raise Same.SAME   (*var is locally bound*)
wenzelm@30146
   641
          else incr_boundvars lev (nth args (i - lev))
wenzelm@19065
   642
            handle Subscript => Bound (i - n))  (*loose: change it*)
wenzelm@19065
   643
      | subst (Abs (a, T, body), lev) = Abs (a, T, subst (body, lev + 1))
wenzelm@19065
   644
      | subst (f $ t, lev) =
wenzelm@32020
   645
          (subst (f, lev) $ (subst (t, lev) handle Same.SAME => t)
wenzelm@32020
   646
            handle Same.SAME => f $ subst (t, lev))
wenzelm@32020
   647
      | subst _ = raise Same.SAME;
wenzelm@32020
   648
  in case args of [] => t | _ => (subst (t, 0) handle Same.SAME => t) end;
clasohm@0
   649
paulson@2192
   650
(*Special case: one argument*)
wenzelm@13000
   651
fun subst_bound (arg, t) : term =
wenzelm@19065
   652
  let
wenzelm@19065
   653
    fun subst (Bound i, lev) =
wenzelm@32020
   654
          if i < lev then raise Same.SAME   (*var is locally bound*)
wenzelm@19065
   655
          else if i = lev then incr_boundvars lev arg
wenzelm@19065
   656
          else Bound (i - 1)   (*loose: change it*)
wenzelm@19065
   657
      | subst (Abs (a, T, body), lev) = Abs (a, T, subst (body, lev + 1))
wenzelm@19065
   658
      | subst (f $ t, lev) =
wenzelm@32020
   659
          (subst (f, lev) $ (subst (t, lev) handle Same.SAME => t)
wenzelm@32020
   660
            handle Same.SAME => f $ subst (t, lev))
wenzelm@32020
   661
      | subst _ = raise Same.SAME;
wenzelm@32020
   662
  in subst (t, 0) handle Same.SAME => t end;
paulson@2192
   663
clasohm@0
   664
(*beta-reduce if possible, else form application*)
paulson@2192
   665
fun betapply (Abs(_,_,t), u) = subst_bound (u,t)
clasohm@0
   666
  | betapply (f,u) = f$u;
clasohm@0
   667
wenzelm@18183
   668
val betapplys = Library.foldl betapply;
wenzelm@18183
   669
wenzelm@14786
   670
haftmann@20109
   671
(*unfolding abstractions with substitution
haftmann@20109
   672
  of bound variables and implicit eta-expansion*)
haftmann@20109
   673
fun strip_abs_eta k t =
haftmann@20109
   674
  let
wenzelm@29278
   675
    val used = fold_aterms declare_term_frees t Name.context;
haftmann@20109
   676
    fun strip_abs t (0, used) = (([], t), (0, used))
haftmann@20109
   677
      | strip_abs (Abs (v, T, t)) (k, used) =
haftmann@20109
   678
          let
wenzelm@20122
   679
            val ([v'], used') = Name.variants [v] used;
haftmann@21013
   680
            val t' = subst_bound (Free (v', T), t);
wenzelm@20122
   681
            val ((vs, t''), (k', used'')) = strip_abs t' (k - 1, used');
wenzelm@20122
   682
          in (((v', T) :: vs, t''), (k', used'')) end
haftmann@20109
   683
      | strip_abs t (k, used) = (([], t), (k, used));
haftmann@20109
   684
    fun expand_eta [] t _ = ([], t)
haftmann@20109
   685
      | expand_eta (T::Ts) t used =
haftmann@20109
   686
          let
wenzelm@20122
   687
            val ([v], used') = Name.variants [""] used;
wenzelm@20122
   688
            val (vs, t') = expand_eta Ts (t $ Free (v, T)) used';
haftmann@20109
   689
          in ((v, T) :: vs, t') end;
haftmann@20109
   690
    val ((vs1, t'), (k', used')) = strip_abs t (k, used);
haftmann@20109
   691
    val Ts = (fst o chop k' o fst o strip_type o fastype_of) t';
haftmann@20109
   692
    val (vs2, t'') = expand_eta Ts t' used';
haftmann@20109
   693
  in (vs1 @ vs2, t'') end;
haftmann@20109
   694
haftmann@20109
   695
clasohm@0
   696
(*Substitute new for free occurrences of old in a term*)
wenzelm@29256
   697
fun subst_free [] = I
clasohm@0
   698
  | subst_free pairs =
wenzelm@13000
   699
      let fun substf u =
haftmann@17314
   700
            case AList.lookup (op aconv) pairs u of
skalberg@15531
   701
                SOME u' => u'
skalberg@15531
   702
              | NONE => (case u of Abs(a,T,t) => Abs(a, T, substf t)
wenzelm@9536
   703
                                 | t$u' => substf t $ substf u'
wenzelm@9536
   704
                                 | _ => u)
clasohm@0
   705
      in  substf  end;
clasohm@0
   706
wenzelm@13000
   707
(*Abstraction of the term "body" over its occurrences of v,
clasohm@0
   708
    which must contain no loose bound variables.
clasohm@0
   709
  The resulting term is ready to become the body of an Abs.*)
wenzelm@16882
   710
fun abstract_over (v, body) =
wenzelm@16882
   711
  let
wenzelm@16990
   712
    fun abs lev tm =
wenzelm@16990
   713
      if v aconv tm then Bound lev
wenzelm@16882
   714
      else
wenzelm@16990
   715
        (case tm of
wenzelm@16990
   716
          Abs (a, T, t) => Abs (a, T, abs (lev + 1) t)
wenzelm@32020
   717
        | t $ u =>
wenzelm@32020
   718
            (abs lev t $ (abs lev u handle Same.SAME => u)
wenzelm@32020
   719
              handle Same.SAME => t $ abs lev u)
wenzelm@32020
   720
        | _ => raise Same.SAME);
wenzelm@32020
   721
  in abs 0 body handle Same.SAME => body end;
clasohm@0
   722
wenzelm@32198
   723
fun term_name (Const (x, _)) = Long_Name.base_name x
wenzelm@32198
   724
  | term_name (Free (x, _)) = x
wenzelm@32198
   725
  | term_name (Var ((x, _), _)) = x
wenzelm@32198
   726
  | term_name _ = Name.uu;
wenzelm@32198
   727
wenzelm@32198
   728
fun lambda_name (x, v) t =
wenzelm@32198
   729
  Abs (if x = "" then term_name v else x, fastype_of v, abstract_over (v, t));
wenzelm@32198
   730
wenzelm@32198
   731
fun lambda v t = lambda_name ("", v) t;
clasohm@0
   732
clasohm@0
   733
(*Form an abstraction over a free variable.*)
wenzelm@21975
   734
fun absfree (a,T,body) = Abs (a, T, abstract_over (Free (a, T), body));
wenzelm@24850
   735
fun absdummy (T, body) = Abs (Name.internal Name.uu, T, body);
clasohm@0
   736
clasohm@0
   737
(*Abstraction over a list of free variables*)
clasohm@0
   738
fun list_abs_free ([ ] ,     t) = t
wenzelm@13000
   739
  | list_abs_free ((a,T)::vars, t) =
clasohm@0
   740
      absfree(a, T, list_abs_free(vars,t));
clasohm@0
   741
clasohm@0
   742
(*Quantification over a list of free variables*)
clasohm@0
   743
fun list_all_free ([], t: term) = t
wenzelm@13000
   744
  | list_all_free ((a,T)::vars, t) =
clasohm@0
   745
        (all T) $ (absfree(a, T, list_all_free(vars,t)));
clasohm@0
   746
clasohm@0
   747
(*Quantification over a list of variables (already bound in body) *)
clasohm@0
   748
fun list_all ([], t) = t
wenzelm@13000
   749
  | list_all ((a,T)::vars, t) =
clasohm@0
   750
        (all T) $ (Abs(a, T, list_all(vars,t)));
clasohm@0
   751
wenzelm@16678
   752
(*Replace the ATOMIC term ti by ui;    inst = [(t1,u1), ..., (tn,un)].
clasohm@0
   753
  A simultaneous substitution:  [ (a,b), (b,a) ] swaps a and b.  *)
wenzelm@16678
   754
fun subst_atomic [] tm = tm
wenzelm@16678
   755
  | subst_atomic inst tm =
wenzelm@16678
   756
      let
wenzelm@16678
   757
        fun subst (Abs (a, T, body)) = Abs (a, T, subst body)
wenzelm@16678
   758
          | subst (t $ u) = subst t $ subst u
wenzelm@18942
   759
          | subst t = the_default t (AList.lookup (op aconv) inst t);
wenzelm@16678
   760
      in subst tm end;
clasohm@0
   761
wenzelm@16678
   762
(*Replace the ATOMIC type Ti by Ui;    inst = [(T1,U1), ..., (Tn,Un)].*)
wenzelm@16678
   763
fun typ_subst_atomic [] ty = ty
wenzelm@16678
   764
  | typ_subst_atomic inst ty =
wenzelm@16678
   765
      let
wenzelm@16678
   766
        fun subst (Type (a, Ts)) = Type (a, map subst Ts)
wenzelm@18942
   767
          | subst T = the_default T (AList.lookup (op = : typ * typ -> bool) inst T);
wenzelm@16678
   768
      in subst ty end;
berghofe@15797
   769
wenzelm@16678
   770
fun subst_atomic_types [] tm = tm
wenzelm@20548
   771
  | subst_atomic_types inst tm = map_types (typ_subst_atomic inst) tm;
wenzelm@16678
   772
wenzelm@16678
   773
fun typ_subst_TVars [] ty = ty
wenzelm@16678
   774
  | typ_subst_TVars inst ty =
wenzelm@16678
   775
      let
wenzelm@16678
   776
        fun subst (Type (a, Ts)) = Type (a, map subst Ts)
wenzelm@18942
   777
          | subst (T as TVar (xi, _)) = the_default T (AList.lookup (op =) inst xi)
wenzelm@16678
   778
          | subst T = T;
wenzelm@16678
   779
      in subst ty end;
clasohm@0
   780
wenzelm@16678
   781
fun subst_TVars [] tm = tm
wenzelm@20548
   782
  | subst_TVars inst tm = map_types (typ_subst_TVars inst) tm;
clasohm@0
   783
wenzelm@16678
   784
fun subst_Vars [] tm = tm
wenzelm@16678
   785
  | subst_Vars inst tm =
wenzelm@16678
   786
      let
wenzelm@18942
   787
        fun subst (t as Var (xi, _)) = the_default t (AList.lookup (op =) inst xi)
wenzelm@16678
   788
          | subst (Abs (a, T, t)) = Abs (a, T, subst t)
wenzelm@16678
   789
          | subst (t $ u) = subst t $ subst u
wenzelm@16678
   790
          | subst t = t;
wenzelm@16678
   791
      in subst tm end;
clasohm@0
   792
wenzelm@16678
   793
fun subst_vars ([], []) tm = tm
wenzelm@16678
   794
  | subst_vars ([], inst) tm = subst_Vars inst tm
wenzelm@16678
   795
  | subst_vars (instT, inst) tm =
wenzelm@16678
   796
      let
wenzelm@16678
   797
        fun subst (Const (a, T)) = Const (a, typ_subst_TVars instT T)
wenzelm@16678
   798
          | subst (Free (a, T)) = Free (a, typ_subst_TVars instT T)
wenzelm@32784
   799
          | subst (Var (xi, T)) =
haftmann@17271
   800
              (case AList.lookup (op =) inst xi of
wenzelm@16678
   801
                NONE => Var (xi, typ_subst_TVars instT T)
wenzelm@16678
   802
              | SOME t => t)
wenzelm@16678
   803
          | subst (t as Bound _) = t
wenzelm@16678
   804
          | subst (Abs (a, T, t)) = Abs (a, typ_subst_TVars instT T, subst t)
wenzelm@16678
   805
          | subst (t $ u) = subst t $ subst u;
wenzelm@16678
   806
      in subst tm end;
clasohm@0
   807
wenzelm@25050
   808
fun close_schematic_term t =
wenzelm@25050
   809
  let
wenzelm@25050
   810
    val extra_types = map (fn v => Const ("TYPE", itselfT (TVar v))) (hidden_polymorphism t);
wenzelm@30285
   811
    val extra_terms = map Var (add_vars t []);
wenzelm@30285
   812
  in fold lambda (extra_terms @ extra_types) t end;
wenzelm@25050
   813
wenzelm@25050
   814
clasohm@0
   815
paulson@15573
   816
(** Identifying first-order terms **)
paulson@15573
   817
wenzelm@20199
   818
(*Differs from proofterm/is_fun in its treatment of TVar*)
wenzelm@29256
   819
fun is_funtype (Type ("fun", [_, _])) = true
wenzelm@20199
   820
  | is_funtype _ = false;
wenzelm@20199
   821
paulson@15573
   822
(*Argument Ts is a reverse list of binder types, needed if term t contains Bound vars*)
wenzelm@29256
   823
fun has_not_funtype Ts t = not (is_funtype (fastype_of1 (Ts, t)));
paulson@15573
   824
wenzelm@16537
   825
(*First order means in all terms of the form f(t1,...,tn) no argument has a
paulson@16589
   826
  function type. The supplied quantifiers are excluded: their argument always
paulson@16589
   827
  has a function type through a recursive call into its body.*)
wenzelm@16667
   828
fun is_first_order quants =
paulson@16589
   829
  let fun first_order1 Ts (Abs (_,T,body)) = first_order1 (T::Ts) body
wenzelm@16667
   830
        | first_order1 Ts (Const(q,_) $ Abs(a,T,body)) =
wenzelm@20664
   831
            member (op =) quants q  andalso   (*it is a known quantifier*)
paulson@16589
   832
            not (is_funtype T)   andalso first_order1 (T::Ts) body
wenzelm@16667
   833
        | first_order1 Ts t =
wenzelm@16667
   834
            case strip_comb t of
wenzelm@16667
   835
                 (Var _, ts) => forall (first_order1 Ts andf has_not_funtype Ts) ts
wenzelm@16667
   836
               | (Free _, ts) => forall (first_order1 Ts andf has_not_funtype Ts) ts
wenzelm@16667
   837
               | (Const _, ts) => forall (first_order1 Ts andf has_not_funtype Ts) ts
wenzelm@16667
   838
               | (Bound _, ts) => forall (first_order1 Ts andf has_not_funtype Ts) ts
wenzelm@16667
   839
               | (Abs _, ts) => false (*not in beta-normal form*)
wenzelm@16667
   840
               | _ => error "first_order: unexpected case"
paulson@16589
   841
    in  first_order1 []  end;
paulson@15573
   842
wenzelm@16710
   843
wenzelm@16990
   844
(* maximum index of typs and terms *)
clasohm@0
   845
wenzelm@16710
   846
fun maxidx_typ (TVar ((_, j), _)) i = Int.max (i, j)
wenzelm@16710
   847
  | maxidx_typ (Type (_, Ts)) i = maxidx_typs Ts i
wenzelm@16710
   848
  | maxidx_typ (TFree _) i = i
wenzelm@16710
   849
and maxidx_typs [] i = i
wenzelm@16710
   850
  | maxidx_typs (T :: Ts) i = maxidx_typs Ts (maxidx_typ T i);
clasohm@0
   851
wenzelm@16710
   852
fun maxidx_term (Var ((_, j), T)) i = maxidx_typ T (Int.max (i, j))
wenzelm@16710
   853
  | maxidx_term (Const (_, T)) i = maxidx_typ T i
wenzelm@16710
   854
  | maxidx_term (Free (_, T)) i = maxidx_typ T i
wenzelm@16710
   855
  | maxidx_term (Bound _) i = i
wenzelm@16710
   856
  | maxidx_term (Abs (_, T, t)) i = maxidx_term t (maxidx_typ T i)
wenzelm@16710
   857
  | maxidx_term (t $ u) i = maxidx_term u (maxidx_term t i);
clasohm@0
   858
wenzelm@16710
   859
fun maxidx_of_typ T = maxidx_typ T ~1;
wenzelm@16710
   860
fun maxidx_of_typs Ts = maxidx_typs Ts ~1;
wenzelm@16710
   861
fun maxidx_of_term t = maxidx_term t ~1;
berghofe@13665
   862
clasohm@0
   863
clasohm@0
   864
wenzelm@29270
   865
(** misc syntax operations **)
clasohm@0
   866
wenzelm@19909
   867
(* substructure *)
wenzelm@4017
   868
wenzelm@19909
   869
fun exists_subtype P =
wenzelm@19909
   870
  let
wenzelm@19909
   871
    fun ex ty = P ty orelse
wenzelm@19909
   872
      (case ty of Type (_, Ts) => exists ex Ts | _ => false);
wenzelm@19909
   873
  in ex end;
nipkow@13646
   874
wenzelm@20531
   875
fun exists_type P =
wenzelm@20531
   876
  let
wenzelm@20531
   877
    fun ex (Const (_, T)) = P T
wenzelm@20531
   878
      | ex (Free (_, T)) = P T
wenzelm@20531
   879
      | ex (Var (_, T)) = P T
wenzelm@20531
   880
      | ex (Bound _) = false
wenzelm@20531
   881
      | ex (Abs (_, T, t)) = P T orelse ex t
wenzelm@20531
   882
      | ex (t $ u) = ex t orelse ex u;
wenzelm@20531
   883
  in ex end;
wenzelm@20531
   884
wenzelm@16943
   885
fun exists_subterm P =
wenzelm@16943
   886
  let
wenzelm@16943
   887
    fun ex tm = P tm orelse
wenzelm@16943
   888
      (case tm of
wenzelm@16943
   889
        t $ u => ex t orelse ex u
wenzelm@16943
   890
      | Abs (_, _, t) => ex t
wenzelm@16943
   891
      | _ => false);
wenzelm@16943
   892
  in ex end;
obua@16108
   893
wenzelm@29270
   894
fun exists_Const P = exists_subterm (fn Const c => P c | _ => false);
wenzelm@29270
   895
wenzelm@24671
   896
fun has_abs (Abs _) = true
wenzelm@24671
   897
  | has_abs (t $ u) = has_abs t orelse has_abs u
wenzelm@24671
   898
  | has_abs _ = false;
wenzelm@24671
   899
wenzelm@24671
   900
wenzelm@20199
   901
(* dest abstraction *)
clasohm@0
   902
wenzelm@16678
   903
fun dest_abs (x, T, body) =
wenzelm@16678
   904
  let
wenzelm@16678
   905
    fun name_clash (Free (y, _)) = (x = y)
wenzelm@16678
   906
      | name_clash (t $ u) = name_clash t orelse name_clash u
wenzelm@16678
   907
      | name_clash (Abs (_, _, t)) = name_clash t
wenzelm@16678
   908
      | name_clash _ = false;
wenzelm@16678
   909
  in
wenzelm@27335
   910
    if name_clash body then dest_abs (Name.variant [x] x, T, body)    (*potentially slow*)
wenzelm@16678
   911
    else (x, subst_bound (Free (x, T), body))
wenzelm@16678
   912
  end;
wenzelm@16678
   913
wenzelm@20160
   914
wenzelm@9536
   915
(* dummy patterns *)
wenzelm@9536
   916
wenzelm@9536
   917
val dummy_patternN = "dummy_pattern";
wenzelm@9536
   918
wenzelm@18253
   919
fun dummy_pattern T = Const (dummy_patternN, T);
wenzelm@18253
   920
wenzelm@9536
   921
fun is_dummy_pattern (Const ("dummy_pattern", _)) = true
wenzelm@9536
   922
  | is_dummy_pattern _ = false;
wenzelm@9536
   923
wenzelm@9536
   924
fun no_dummy_patterns tm =
haftmann@16787
   925
  if not (fold_aterms (fn t => fn b => b orelse is_dummy_pattern t) tm false) then tm
wenzelm@9536
   926
  else raise TERM ("Illegal occurrence of '_' dummy pattern", [tm]);
wenzelm@9536
   927
wenzelm@24733
   928
fun free_dummy_patterns (Const ("dummy_pattern", T)) used =
wenzelm@24850
   929
      let val [x] = Name.invents used Name.uu 1
wenzelm@24733
   930
      in (Free (Name.internal x, T), Name.declare x used) end
wenzelm@24733
   931
  | free_dummy_patterns (Abs (x, T, b)) used =
wenzelm@24733
   932
      let val (b', used') = free_dummy_patterns b used
wenzelm@24733
   933
      in (Abs (x, T, b'), used') end
wenzelm@24733
   934
  | free_dummy_patterns (t $ u) used =
wenzelm@24733
   935
      let
wenzelm@24733
   936
        val (t', used') = free_dummy_patterns t used;
wenzelm@24733
   937
        val (u', used'') = free_dummy_patterns u used';
wenzelm@24733
   938
      in (t' $ u', used'') end
wenzelm@24733
   939
  | free_dummy_patterns a used = (a, used);
wenzelm@24733
   940
wenzelm@24762
   941
fun replace_dummy Ts (Const ("dummy_pattern", T)) i =
wenzelm@24762
   942
      (list_comb (Var (("_dummy_", i), Ts ---> T), map Bound (0 upto length Ts - 1)), i + 1)
wenzelm@24762
   943
  | replace_dummy Ts (Abs (x, T, t)) i =
wenzelm@24762
   944
      let val (t', i') = replace_dummy (T :: Ts) t i
wenzelm@24762
   945
      in (Abs (x, T, t'), i') end
wenzelm@24762
   946
  | replace_dummy Ts (t $ u) i =
wenzelm@24762
   947
      let
wenzelm@24762
   948
        val (t', i') = replace_dummy Ts t i;
wenzelm@24762
   949
        val (u', i'') = replace_dummy Ts u i';
wenzelm@24762
   950
      in (t' $ u', i'') end
wenzelm@24762
   951
  | replace_dummy _ a i = (a, i);
wenzelm@11903
   952
wenzelm@11903
   953
val replace_dummy_patterns = replace_dummy [];
wenzelm@9536
   954
wenzelm@10552
   955
fun is_replaced_dummy_pattern ("_dummy_", _) = true
wenzelm@10552
   956
  | is_replaced_dummy_pattern _ = false;
wenzelm@9536
   957
wenzelm@16035
   958
fun show_dummy_patterns (Var (("_dummy_", _), T)) = Const ("dummy_pattern", T)
wenzelm@16035
   959
  | show_dummy_patterns (t $ u) = show_dummy_patterns t $ show_dummy_patterns u
wenzelm@16035
   960
  | show_dummy_patterns (Abs (x, T, t)) = Abs (x, T, show_dummy_patterns t)
wenzelm@16035
   961
  | show_dummy_patterns a = a;
wenzelm@16035
   962
wenzelm@13484
   963
wenzelm@20100
   964
(* display variables *)
wenzelm@20100
   965
wenzelm@32738
   966
val show_question_marks = Unsynchronized.ref true;
berghofe@15472
   967
wenzelm@14786
   968
fun string_of_vname (x, i) =
wenzelm@14786
   969
  let
wenzelm@15986
   970
    val question_mark = if ! show_question_marks then "?" else "";
wenzelm@15986
   971
    val idx = string_of_int i;
wenzelm@15986
   972
    val dot =
wenzelm@15986
   973
      (case rev (Symbol.explode x) of
wenzelm@15986
   974
        _ :: "\\<^isub>" :: _ => false
wenzelm@15986
   975
      | _ :: "\\<^isup>" :: _ => false
wenzelm@15986
   976
      | c :: _ => Symbol.is_digit c
wenzelm@15986
   977
      | _ => true);
wenzelm@14786
   978
  in
wenzelm@15986
   979
    if dot then question_mark ^ x ^ "." ^ idx
wenzelm@15986
   980
    else if i <> 0 then question_mark ^ x ^ idx
wenzelm@15986
   981
    else question_mark ^ x
wenzelm@14786
   982
  end;
wenzelm@14786
   983
wenzelm@14786
   984
fun string_of_vname' (x, ~1) = x
wenzelm@14786
   985
  | string_of_vname' xi = string_of_vname xi;
wenzelm@14786
   986
clasohm@1364
   987
end;
clasohm@1364
   988
wenzelm@4444
   989
structure BasicTerm: BASIC_TERM = Term;
wenzelm@4444
   990
open BasicTerm;