src/Pure/term.ML
author wenzelm
Wed Dec 31 18:53:16 2008 +0100 (2008-12-31)
changeset 29270 0eade173f77e
parent 29269 5c25a2012975
child 29278 e9d148a808eb
permissions -rw-r--r--
moved old add_type_XXX, add_term_XXX etc. to structure OldTerm;
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(*  Title:      Pure/term.ML
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    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
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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 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 rename_wrt_term: term -> (string * 'a) list -> (string * 'a) list
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  val show_question_marks: bool 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 hidden_polymorphism: term -> (indexname * sort) 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 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 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 variant_frees: term -> (string * 'a) list -> (string * 'a) list
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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) = (List.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
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  | fastype_of1 (Ts, Bound i) = (List.nth(Ts,i)
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         handle Subscript => raise TERM("fastype_of: Bound", [Bound i]))
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  | fastype_of1 (_, Var (_,T)) = T
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  | fastype_of1 (Ts, Abs (_,T,u)) = T --> fastype_of1 (T::Ts, u);
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fun fastype_of t : typ = fastype_of1 ([],t);
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   326
wenzelm@16678
   327
(*Determine the argument type of a function*)
wenzelm@22908
   328
fun argument_type_of tm k =
wenzelm@16678
   329
  let
wenzelm@16678
   330
    fun argT i (Type ("fun", [T, U])) = if i = 0 then T else argT (i - 1) U
wenzelm@16678
   331
      | argT _ T = raise TYPE ("argument_type_of", [T], []);
wenzelm@16678
   332
wenzelm@16678
   333
    fun arg 0 _ (Abs (_, T, _)) = T
wenzelm@16678
   334
      | arg i Ts (Abs (_, T, t)) = arg (i - 1) (T :: Ts) t
wenzelm@16678
   335
      | arg i Ts (t $ _) = arg (i + 1) Ts t
wenzelm@16678
   336
      | arg i Ts a = argT i (fastype_of1 (Ts, a));
wenzelm@22908
   337
  in arg k [] tm end;
wenzelm@16678
   338
clasohm@0
   339
wenzelm@19473
   340
val list_abs = uncurry (fold_rev (fn (x, T) => fn t => Abs (x, T, t)));
wenzelm@10806
   341
haftmann@18927
   342
fun strip_abs (Abs (a, T, t)) =
haftmann@18927
   343
      let val (a', t') = strip_abs t
haftmann@18927
   344
      in ((a, T) :: a', t') end
haftmann@18927
   345
  | strip_abs t = ([], t);
haftmann@18927
   346
clasohm@0
   347
(* maps  (x1,...,xn)t   to   t  *)
wenzelm@13000
   348
fun strip_abs_body (Abs(_,_,t))  =  strip_abs_body t
clasohm@0
   349
  | strip_abs_body u  =  u;
clasohm@0
   350
clasohm@0
   351
(* maps  (x1,...,xn)t   to   [x1, ..., xn]  *)
wenzelm@13000
   352
fun strip_abs_vars (Abs(a,T,t))  =  (a,T) :: strip_abs_vars t
clasohm@0
   353
  | strip_abs_vars u  =  [] : (string*typ) list;
clasohm@0
   354
clasohm@0
   355
clasohm@0
   356
fun strip_qnt_body qnt =
clasohm@0
   357
let fun strip(tm as Const(c,_)$Abs(_,_,t)) = if c=qnt then strip t else tm
clasohm@0
   358
      | strip t = t
clasohm@0
   359
in strip end;
clasohm@0
   360
clasohm@0
   361
fun strip_qnt_vars qnt =
clasohm@0
   362
let fun strip(Const(c,_)$Abs(a,T,t)) = if c=qnt then (a,T)::strip t else []
clasohm@0
   363
      | strip t  =  [] : (string*typ) list
clasohm@0
   364
in strip end;
clasohm@0
   365
clasohm@0
   366
clasohm@0
   367
(* maps   (f, [t1,...,tn])  to  f(t1,...,tn) *)
skalberg@15570
   368
val list_comb : term * term list -> term = Library.foldl (op $);
clasohm@0
   369
clasohm@0
   370
clasohm@0
   371
(* maps   f(t1,...,tn)  to  (f, [t1,...,tn]) ; naturally tail-recursive*)
wenzelm@13000
   372
fun strip_comb u : term * term list =
clasohm@0
   373
    let fun stripc (f$t, ts) = stripc (f, t::ts)
wenzelm@13000
   374
        |   stripc  x =  x
clasohm@0
   375
    in  stripc(u,[])  end;
clasohm@0
   376
clasohm@0
   377
clasohm@0
   378
(* maps   f(t1,...,tn)  to  f , which is never a combination *)
clasohm@0
   379
fun head_of (f$t) = head_of f
clasohm@0
   380
  | head_of u = u;
clasohm@0
   381
wenzelm@16599
   382
(*number of atoms and abstractions in a term*)
wenzelm@16599
   383
fun size_of_term tm =
wenzelm@16599
   384
  let
wenzelm@16678
   385
    fun add_size (t $ u, n) = add_size (t, add_size (u, n))
wenzelm@16678
   386
      | add_size (Abs (_ ,_, t), n) = add_size (t, n + 1)
wenzelm@16678
   387
      | add_size (_, n) = n + 1;
wenzelm@16678
   388
  in add_size (tm, 0) end;
clasohm@0
   389
haftmann@18847
   390
fun map_atyps f (Type (a, Ts)) = Type (a, map (map_atyps f) Ts)
haftmann@18976
   391
  | map_atyps f T = f T;
haftmann@18847
   392
haftmann@18847
   393
fun map_aterms f (t $ u) = map_aterms f t $ map_aterms f u
haftmann@18847
   394
  | map_aterms f (Abs (a, T, t)) = Abs (a, T, map_aterms f t)
haftmann@18847
   395
  | map_aterms f t = f t;
haftmann@18847
   396
wenzelm@18981
   397
fun map_type_tvar f = map_atyps (fn TVar x => f x | T => T);
wenzelm@18981
   398
fun map_type_tfree f = map_atyps (fn TFree x => f x | T => T);
nipkow@949
   399
wenzelm@20548
   400
fun map_types f =
wenzelm@16678
   401
  let
wenzelm@16678
   402
    fun map_aux (Const (a, T)) = Const (a, f T)
wenzelm@16678
   403
      | map_aux (Free (a, T)) = Free (a, f T)
wenzelm@16678
   404
      | map_aux (Var (v, T)) = Var (v, f T)
wenzelm@16678
   405
      | map_aux (t as Bound _)  = t
wenzelm@16678
   406
      | map_aux (Abs (a, T, t)) = Abs (a, f T, map_aux t)
wenzelm@16678
   407
      | map_aux (t $ u) = map_aux t $ map_aux u;
wenzelm@16678
   408
  in map_aux end;
clasohm@0
   409
clasohm@0
   410
wenzelm@16943
   411
(* fold types and terms *)
wenzelm@16943
   412
wenzelm@16943
   413
fun fold_atyps f (Type (_, Ts)) = fold (fold_atyps f) Ts
wenzelm@16943
   414
  | fold_atyps f T = f T;
wenzelm@16943
   415
wenzelm@16943
   416
fun fold_aterms f (t $ u) = fold_aterms f t #> fold_aterms f u
wenzelm@16943
   417
  | fold_aterms f (Abs (_, _, t)) = fold_aterms f t
wenzelm@16943
   418
  | fold_aterms f a = f a;
wenzelm@16943
   419
wenzelm@16943
   420
fun fold_term_types f (t as Const (_, T)) = f t T
wenzelm@16943
   421
  | fold_term_types f (t as Free (_, T)) = f t T
wenzelm@16943
   422
  | fold_term_types f (t as Var (_, T)) = f t T
wenzelm@16943
   423
  | fold_term_types f (Bound _) = I
wenzelm@16943
   424
  | fold_term_types f (t as Abs (_, T, b)) = f t T #> fold_term_types f b
wenzelm@16943
   425
  | fold_term_types f (t $ u) = fold_term_types f t #> fold_term_types f u;
wenzelm@16943
   426
wenzelm@16943
   427
fun fold_types f = fold_term_types (K f);
wenzelm@16943
   428
wenzelm@24483
   429
fun replace_types (Const (c, _)) (T :: Ts) = (Const (c, T), Ts)
wenzelm@24483
   430
  | replace_types (Free (x, _)) (T :: Ts) = (Free (x, T), Ts)
wenzelm@24483
   431
  | replace_types (Var (xi, _)) (T :: Ts) = (Var (xi, T), Ts)
wenzelm@24483
   432
  | replace_types (Bound i) Ts = (Bound i, Ts)
wenzelm@24483
   433
  | replace_types (Abs (x, _, b)) (T :: Ts) =
wenzelm@24483
   434
      let val (b', Ts') = replace_types b Ts
wenzelm@24483
   435
      in (Abs (x, T, b'), Ts') end
wenzelm@24483
   436
  | replace_types (t $ u) Ts =
wenzelm@24483
   437
      let
wenzelm@24483
   438
        val (t', Ts') = replace_types t Ts;
wenzelm@24483
   439
        val (u', Ts'') = replace_types u Ts';
wenzelm@24483
   440
      in (t' $ u', Ts'') end;
wenzelm@24483
   441
wenzelm@24483
   442
fun burrow_types f ts =
wenzelm@24483
   443
  let
wenzelm@24483
   444
    val Ts = rev (fold (fold_types cons) ts []);
wenzelm@24483
   445
    val Ts' = f Ts;
wenzelm@24483
   446
    val (ts', []) = fold_map replace_types ts Ts';
wenzelm@24483
   447
  in ts' end;
wenzelm@24483
   448
wenzelm@16943
   449
(*collect variables*)
wenzelm@29257
   450
val add_tvar_namesT = fold_atyps (fn TVar (xi, _) => insert (op =) xi | _ => I);
wenzelm@29257
   451
val add_tvar_names = fold_types add_tvar_namesT;
wenzelm@16943
   452
val add_tvarsT = fold_atyps (fn TVar v => insert (op =) v | _ => I);
wenzelm@16943
   453
val add_tvars = fold_types add_tvarsT;
wenzelm@29257
   454
val add_var_names = fold_aterms (fn Var (xi, _) => insert (op =) xi | _ => I);
wenzelm@16943
   455
val add_vars = fold_aterms (fn Var v => insert (op =) v | _ => I);
wenzelm@29257
   456
val add_tfree_namesT = fold_atyps (fn TFree (xi, _) => insert (op =) xi | _ => I);
wenzelm@29257
   457
val add_tfree_names = fold_types add_tfree_namesT;
wenzelm@16943
   458
val add_tfreesT = fold_atyps (fn TFree v => insert (op =) v | _ => I);
wenzelm@16943
   459
val add_tfrees = fold_types add_tfreesT;
wenzelm@29257
   460
val add_free_names = fold_aterms (fn Free (x, _) => insert (op =) x | _ => I);
wenzelm@16943
   461
val add_frees = fold_aterms (fn Free v => insert (op =) v | _ => I);
wenzelm@16943
   462
wenzelm@25050
   463
(*extra type variables in a term, not covered by its type*)
wenzelm@25050
   464
fun hidden_polymorphism t =
wenzelm@21682
   465
  let
wenzelm@25050
   466
    val T = fastype_of t;
wenzelm@21682
   467
    val tvarsT = add_tvarsT T [];
wenzelm@21682
   468
    val extra_tvars = fold_types (fold_atyps
wenzelm@21682
   469
      (fn TVar v => if member (op =) tvarsT v then I else insert (op =) v | _ => I)) t [];
wenzelm@21682
   470
  in extra_tvars end;
wenzelm@21682
   471
wenzelm@16943
   472
wenzelm@25050
   473
wenzelm@29269
   474
(** Comparing terms **)
wenzelm@29269
   475
wenzelm@29269
   476
(* variables *)
wenzelm@29269
   477
wenzelm@29269
   478
fun eq_ix ((x, i): indexname, (y, j)) = i = j andalso x = y;
wenzelm@16537
   479
wenzelm@29269
   480
fun eq_tvar ((xi, S: sort), (xi', S')) = eq_ix (xi, xi') andalso S = S';
wenzelm@29269
   481
fun eq_var ((xi, T: typ), (xi', T')) = eq_ix (xi, xi') andalso T = T';
wenzelm@29269
   482
wenzelm@29269
   483
wenzelm@29269
   484
(* alpha equivalence *)
wenzelm@20511
   485
wenzelm@20511
   486
fun tm1 aconv tm2 =
wenzelm@20511
   487
  pointer_eq (tm1, tm2) orelse
wenzelm@20511
   488
    (case (tm1, tm2) of
wenzelm@20511
   489
      (t1 $ u1, t2 $ u2) => t1 aconv t2 andalso u1 aconv u2
wenzelm@20511
   490
    | (Abs (_, T1, t1), Abs (_, T2, t2)) => t1 aconv t2 andalso T1 = T2
wenzelm@20511
   491
    | (a1, a2) => a1 = a2);
wenzelm@20511
   492
wenzelm@20511
   493
wenzelm@29269
   494
(*A fast unification filter: true unless the two terms cannot be unified.
wenzelm@29269
   495
  Terms must be NORMAL.  Treats all Vars as distinct. *)
wenzelm@29269
   496
fun could_unify (t, u) =
wenzelm@29269
   497
  let
wenzelm@29269
   498
    fun matchrands (f $ t) (g $ u) = could_unify (t, u) andalso matchrands f g
wenzelm@29269
   499
      | matchrands _ _ = true;
wenzelm@29269
   500
  in
wenzelm@29269
   501
    case (head_of t, head_of u) of
wenzelm@29269
   502
      (_, Var _) => true
wenzelm@29269
   503
    | (Var _, _) => true
wenzelm@29269
   504
    | (Const (a, _), Const (b, _)) => a = b andalso matchrands t u
wenzelm@29269
   505
    | (Free (a, _), Free (b, _)) => a = b andalso matchrands t u
wenzelm@29269
   506
    | (Bound i, Bound j) => i = j andalso matchrands t u
wenzelm@29269
   507
    | (Abs _, _) => true   (*because of possible eta equality*)
wenzelm@29269
   508
    | (_, Abs _) => true
wenzelm@29269
   509
    | _ => false
wenzelm@29269
   510
  end;
wenzelm@16678
   511
nipkow@16570
   512
wenzelm@16537
   513
clasohm@0
   514
(** Connectives of higher order logic **)
clasohm@0
   515
wenzelm@24850
   516
fun aT S = TFree (Name.aT, S);
wenzelm@19394
   517
wenzelm@375
   518
fun itselfT ty = Type ("itself", [ty]);
wenzelm@24850
   519
val a_itselfT = itselfT (TFree (Name.aT, []));
wenzelm@375
   520
clasohm@0
   521
val propT : typ = Type("prop",[]);
clasohm@0
   522
clasohm@0
   523
fun all T = Const("all", (T-->propT)-->propT);
clasohm@0
   524
clasohm@0
   525
(* maps  !!x1...xn. t   to   t  *)
wenzelm@13000
   526
fun strip_all_body (Const("all",_)$Abs(_,_,t))  =  strip_all_body t
clasohm@0
   527
  | strip_all_body t  =  t;
clasohm@0
   528
clasohm@0
   529
(* maps  !!x1...xn. t   to   [x1, ..., xn]  *)
clasohm@0
   530
fun strip_all_vars (Const("all",_)$Abs(a,T,t))  =
wenzelm@13000
   531
                (a,T) :: strip_all_vars t
clasohm@0
   532
  | strip_all_vars t  =  [] : (string*typ) list;
clasohm@0
   533
clasohm@0
   534
(*increments a term's non-local bound variables
clasohm@0
   535
  required when moving a term within abstractions
clasohm@0
   536
     inc is  increment for bound variables
clasohm@0
   537
     lev is  level at which a bound variable is considered 'loose'*)
wenzelm@13000
   538
fun incr_bv (inc, lev, u as Bound i) = if i>=lev then Bound(i+inc) else u
clasohm@0
   539
  | incr_bv (inc, lev, Abs(a,T,body)) =
wenzelm@9536
   540
        Abs(a, T, incr_bv(inc,lev+1,body))
wenzelm@13000
   541
  | incr_bv (inc, lev, f$t) =
clasohm@0
   542
      incr_bv(inc,lev,f) $ incr_bv(inc,lev,t)
clasohm@0
   543
  | incr_bv (inc, lev, u) = u;
clasohm@0
   544
clasohm@0
   545
fun incr_boundvars  0  t = t
clasohm@0
   546
  | incr_boundvars inc t = incr_bv(inc,0,t);
clasohm@0
   547
wenzelm@12981
   548
(*Scan a pair of terms; while they are similar,
wenzelm@12981
   549
  accumulate corresponding bound vars in "al"*)
wenzelm@12981
   550
fun match_bvs(Abs(x,_,s),Abs(y,_,t), al) =
wenzelm@12981
   551
      match_bvs(s, t, if x="" orelse y="" then al
wenzelm@12981
   552
                                          else (x,y)::al)
wenzelm@12981
   553
  | match_bvs(f$s, g$t, al) = match_bvs(f,g,match_bvs(s,t,al))
wenzelm@12981
   554
  | match_bvs(_,_,al) = al;
wenzelm@12981
   555
wenzelm@12981
   556
(* strip abstractions created by parameters *)
wenzelm@12981
   557
fun match_bvars((s,t),al) = match_bvs(strip_abs_body s, strip_abs_body t, al);
wenzelm@12981
   558
haftmann@22031
   559
fun map_abs_vars f (t $ u) = map_abs_vars f t $ map_abs_vars f u
haftmann@22031
   560
  | map_abs_vars f (Abs (a, T, t)) = Abs (f a, T, map_abs_vars f t)
haftmann@22031
   561
  | map_abs_vars f t = t;
haftmann@22031
   562
wenzelm@12981
   563
fun rename_abs pat obj t =
wenzelm@12981
   564
  let
wenzelm@12981
   565
    val ren = match_bvs (pat, obj, []);
wenzelm@12981
   566
    fun ren_abs (Abs (x, T, b)) =
wenzelm@18942
   567
          Abs (the_default x (AList.lookup (op =) ren x), T, ren_abs b)
wenzelm@12981
   568
      | ren_abs (f $ t) = ren_abs f $ ren_abs t
wenzelm@12981
   569
      | ren_abs t = t
skalberg@15531
   570
  in if null ren then NONE else SOME (ren_abs t) end;
clasohm@0
   571
clasohm@0
   572
(*Accumulate all 'loose' bound vars referring to level 'lev' or beyond.
clasohm@0
   573
   (Bound 0) is loose at level 0 *)
wenzelm@13000
   574
fun add_loose_bnos (Bound i, lev, js) =
haftmann@20854
   575
        if i<lev then js else insert (op =) (i - lev) js
clasohm@0
   576
  | add_loose_bnos (Abs (_,_,t), lev, js) = add_loose_bnos (t, lev+1, js)
clasohm@0
   577
  | add_loose_bnos (f$t, lev, js) =
wenzelm@13000
   578
        add_loose_bnos (f, lev, add_loose_bnos (t, lev, js))
clasohm@0
   579
  | add_loose_bnos (_, _, js) = js;
clasohm@0
   580
clasohm@0
   581
fun loose_bnos t = add_loose_bnos (t, 0, []);
clasohm@0
   582
clasohm@0
   583
(* loose_bvar(t,k) iff t contains a 'loose' bound variable referring to
clasohm@0
   584
   level k or beyond. *)
clasohm@0
   585
fun loose_bvar(Bound i,k) = i >= k
clasohm@0
   586
  | loose_bvar(f$t, k) = loose_bvar(f,k) orelse loose_bvar(t,k)
clasohm@0
   587
  | loose_bvar(Abs(_,_,t),k) = loose_bvar(t,k+1)
clasohm@0
   588
  | loose_bvar _ = false;
clasohm@0
   589
nipkow@2792
   590
fun loose_bvar1(Bound i,k) = i = k
nipkow@2792
   591
  | loose_bvar1(f$t, k) = loose_bvar1(f,k) orelse loose_bvar1(t,k)
nipkow@2792
   592
  | loose_bvar1(Abs(_,_,t),k) = loose_bvar1(t,k+1)
nipkow@2792
   593
  | loose_bvar1 _ = false;
clasohm@0
   594
clasohm@0
   595
(*Substitute arguments for loose bound variables.
clasohm@0
   596
  Beta-reduction of arg(n-1)...arg0 into t replacing (Bound i) with (argi).
wenzelm@4626
   597
  Note that for ((%x y. c) a b), the bound vars in c are x=1 and y=0
wenzelm@9536
   598
        and the appropriate call is  subst_bounds([b,a], c) .
clasohm@0
   599
  Loose bound variables >=n are reduced by "n" to
clasohm@0
   600
     compensate for the disappearance of lambdas.
clasohm@0
   601
*)
wenzelm@13000
   602
fun subst_bounds (args: term list, t) : term =
wenzelm@19065
   603
  let
wenzelm@19065
   604
    exception SAME;
wenzelm@19065
   605
    val n = length args;
wenzelm@19065
   606
    fun subst (t as Bound i, lev) =
wenzelm@19065
   607
         (if i < lev then raise SAME   (*var is locally bound*)
wenzelm@19065
   608
          else incr_boundvars lev (List.nth (args, i - lev))
wenzelm@19065
   609
            handle Subscript => Bound (i - n))  (*loose: change it*)
wenzelm@19065
   610
      | subst (Abs (a, T, body), lev) = Abs (a, T, subst (body, lev + 1))
wenzelm@19065
   611
      | subst (f $ t, lev) =
wenzelm@19065
   612
          (subst (f, lev) $ (subst (t, lev) handle SAME => t) handle SAME => f $ subst (t, lev))
wenzelm@19065
   613
      | subst _ = raise SAME;
wenzelm@19065
   614
  in case args of [] => t | _ => (subst (t, 0) handle SAME => t) end;
clasohm@0
   615
paulson@2192
   616
(*Special case: one argument*)
wenzelm@13000
   617
fun subst_bound (arg, t) : term =
wenzelm@19065
   618
  let
wenzelm@19065
   619
    exception SAME;
wenzelm@19065
   620
    fun subst (Bound i, lev) =
wenzelm@19065
   621
          if i < lev then raise SAME   (*var is locally bound*)
wenzelm@19065
   622
          else if i = lev then incr_boundvars lev arg
wenzelm@19065
   623
          else Bound (i - 1)   (*loose: change it*)
wenzelm@19065
   624
      | subst (Abs (a, T, body), lev) = Abs (a, T, subst (body, lev + 1))
wenzelm@19065
   625
      | subst (f $ t, lev) =
wenzelm@19065
   626
          (subst (f, lev) $ (subst (t, lev) handle SAME => t) handle SAME => f $ subst (t, lev))
wenzelm@19065
   627
      | subst _ = raise SAME;
wenzelm@19065
   628
  in subst (t, 0) handle SAME => t end;
paulson@2192
   629
clasohm@0
   630
(*beta-reduce if possible, else form application*)
paulson@2192
   631
fun betapply (Abs(_,_,t), u) = subst_bound (u,t)
clasohm@0
   632
  | betapply (f,u) = f$u;
clasohm@0
   633
wenzelm@18183
   634
val betapplys = Library.foldl betapply;
wenzelm@18183
   635
wenzelm@14786
   636
haftmann@20109
   637
(*unfolding abstractions with substitution
haftmann@20109
   638
  of bound variables and implicit eta-expansion*)
haftmann@20109
   639
fun strip_abs_eta k t =
haftmann@20109
   640
  let
wenzelm@20122
   641
    val used = fold_aterms (fn Free (v, _) => Name.declare v | _ => I) t Name.context;
haftmann@20109
   642
    fun strip_abs t (0, used) = (([], t), (0, used))
haftmann@20109
   643
      | strip_abs (Abs (v, T, t)) (k, used) =
haftmann@20109
   644
          let
wenzelm@20122
   645
            val ([v'], used') = Name.variants [v] used;
haftmann@21013
   646
            val t' = subst_bound (Free (v', T), t);
wenzelm@20122
   647
            val ((vs, t''), (k', used'')) = strip_abs t' (k - 1, used');
wenzelm@20122
   648
          in (((v', T) :: vs, t''), (k', used'')) end
haftmann@20109
   649
      | strip_abs t (k, used) = (([], t), (k, used));
haftmann@20109
   650
    fun expand_eta [] t _ = ([], t)
haftmann@20109
   651
      | expand_eta (T::Ts) t used =
haftmann@20109
   652
          let
wenzelm@20122
   653
            val ([v], used') = Name.variants [""] used;
wenzelm@20122
   654
            val (vs, t') = expand_eta Ts (t $ Free (v, T)) used';
haftmann@20109
   655
          in ((v, T) :: vs, t') end;
haftmann@20109
   656
    val ((vs1, t'), (k', used')) = strip_abs t (k, used);
haftmann@20109
   657
    val Ts = (fst o chop k' o fst o strip_type o fastype_of) t';
haftmann@20109
   658
    val (vs2, t'') = expand_eta Ts t' used';
haftmann@20109
   659
  in (vs1 @ vs2, t'') end;
haftmann@20109
   660
haftmann@20109
   661
clasohm@0
   662
(*Substitute new for free occurrences of old in a term*)
wenzelm@29256
   663
fun subst_free [] = I
clasohm@0
   664
  | subst_free pairs =
wenzelm@13000
   665
      let fun substf u =
haftmann@17314
   666
            case AList.lookup (op aconv) pairs u of
skalberg@15531
   667
                SOME u' => u'
skalberg@15531
   668
              | NONE => (case u of Abs(a,T,t) => Abs(a, T, substf t)
wenzelm@9536
   669
                                 | t$u' => substf t $ substf u'
wenzelm@9536
   670
                                 | _ => u)
clasohm@0
   671
      in  substf  end;
clasohm@0
   672
wenzelm@13000
   673
(*Abstraction of the term "body" over its occurrences of v,
clasohm@0
   674
    which must contain no loose bound variables.
clasohm@0
   675
  The resulting term is ready to become the body of an Abs.*)
wenzelm@16882
   676
fun abstract_over (v, body) =
wenzelm@16882
   677
  let
wenzelm@16990
   678
    exception SAME;
wenzelm@16990
   679
    fun abs lev tm =
wenzelm@16990
   680
      if v aconv tm then Bound lev
wenzelm@16882
   681
      else
wenzelm@16990
   682
        (case tm of
wenzelm@16990
   683
          Abs (a, T, t) => Abs (a, T, abs (lev + 1) t)
wenzelm@16990
   684
        | t $ u => (abs lev t $ (abs lev u handle SAME => u) handle SAME => t $ abs lev u)
wenzelm@16990
   685
        | _ => raise SAME);
wenzelm@16990
   686
  in abs 0 body handle SAME => body end;
clasohm@0
   687
wenzelm@21975
   688
fun lambda v t =
wenzelm@21975
   689
  let val x =
wenzelm@21975
   690
    (case v of
wenzelm@21975
   691
      Const (x, _) => NameSpace.base x
wenzelm@21975
   692
    | Free (x, _) => x
wenzelm@21975
   693
    | Var ((x, _), _) => x
wenzelm@24850
   694
    | _ => Name.uu)
wenzelm@21975
   695
  in Abs (x, fastype_of v, abstract_over (v, t)) end;
clasohm@0
   696
clasohm@0
   697
(*Form an abstraction over a free variable.*)
wenzelm@21975
   698
fun absfree (a,T,body) = Abs (a, T, abstract_over (Free (a, T), body));
wenzelm@24850
   699
fun absdummy (T, body) = Abs (Name.internal Name.uu, T, body);
clasohm@0
   700
clasohm@0
   701
(*Abstraction over a list of free variables*)
clasohm@0
   702
fun list_abs_free ([ ] ,     t) = t
wenzelm@13000
   703
  | list_abs_free ((a,T)::vars, t) =
clasohm@0
   704
      absfree(a, T, list_abs_free(vars,t));
clasohm@0
   705
clasohm@0
   706
(*Quantification over a list of free variables*)
clasohm@0
   707
fun list_all_free ([], t: term) = t
wenzelm@13000
   708
  | list_all_free ((a,T)::vars, t) =
clasohm@0
   709
        (all T) $ (absfree(a, T, list_all_free(vars,t)));
clasohm@0
   710
clasohm@0
   711
(*Quantification over a list of variables (already bound in body) *)
clasohm@0
   712
fun list_all ([], t) = t
wenzelm@13000
   713
  | list_all ((a,T)::vars, t) =
clasohm@0
   714
        (all T) $ (Abs(a, T, list_all(vars,t)));
clasohm@0
   715
wenzelm@16678
   716
(*Replace the ATOMIC term ti by ui;    inst = [(t1,u1), ..., (tn,un)].
clasohm@0
   717
  A simultaneous substitution:  [ (a,b), (b,a) ] swaps a and b.  *)
wenzelm@16678
   718
fun subst_atomic [] tm = tm
wenzelm@16678
   719
  | subst_atomic inst tm =
wenzelm@16678
   720
      let
wenzelm@16678
   721
        fun subst (Abs (a, T, body)) = Abs (a, T, subst body)
wenzelm@16678
   722
          | subst (t $ u) = subst t $ subst u
wenzelm@18942
   723
          | subst t = the_default t (AList.lookup (op aconv) inst t);
wenzelm@16678
   724
      in subst tm end;
clasohm@0
   725
wenzelm@16678
   726
(*Replace the ATOMIC type Ti by Ui;    inst = [(T1,U1), ..., (Tn,Un)].*)
wenzelm@16678
   727
fun typ_subst_atomic [] ty = ty
wenzelm@16678
   728
  | typ_subst_atomic inst ty =
wenzelm@16678
   729
      let
wenzelm@16678
   730
        fun subst (Type (a, Ts)) = Type (a, map subst Ts)
wenzelm@18942
   731
          | subst T = the_default T (AList.lookup (op = : typ * typ -> bool) inst T);
wenzelm@16678
   732
      in subst ty end;
berghofe@15797
   733
wenzelm@16678
   734
fun subst_atomic_types [] tm = tm
wenzelm@20548
   735
  | subst_atomic_types inst tm = map_types (typ_subst_atomic inst) tm;
wenzelm@16678
   736
wenzelm@16678
   737
fun typ_subst_TVars [] ty = ty
wenzelm@16678
   738
  | typ_subst_TVars inst ty =
wenzelm@16678
   739
      let
wenzelm@16678
   740
        fun subst (Type (a, Ts)) = Type (a, map subst Ts)
wenzelm@18942
   741
          | subst (T as TVar (xi, _)) = the_default T (AList.lookup (op =) inst xi)
wenzelm@16678
   742
          | subst T = T;
wenzelm@16678
   743
      in subst ty end;
clasohm@0
   744
wenzelm@16678
   745
fun subst_TVars [] tm = tm
wenzelm@20548
   746
  | subst_TVars inst tm = map_types (typ_subst_TVars inst) tm;
clasohm@0
   747
wenzelm@16678
   748
fun subst_Vars [] tm = tm
wenzelm@16678
   749
  | subst_Vars inst tm =
wenzelm@16678
   750
      let
wenzelm@18942
   751
        fun subst (t as Var (xi, _)) = the_default t (AList.lookup (op =) inst xi)
wenzelm@16678
   752
          | subst (Abs (a, T, t)) = Abs (a, T, subst t)
wenzelm@16678
   753
          | subst (t $ u) = subst t $ subst u
wenzelm@16678
   754
          | subst t = t;
wenzelm@16678
   755
      in subst tm end;
clasohm@0
   756
wenzelm@16678
   757
fun subst_vars ([], []) tm = tm
wenzelm@16678
   758
  | subst_vars ([], inst) tm = subst_Vars inst tm
wenzelm@16678
   759
  | subst_vars (instT, inst) tm =
wenzelm@16678
   760
      let
wenzelm@16678
   761
        fun subst (Const (a, T)) = Const (a, typ_subst_TVars instT T)
wenzelm@16678
   762
          | subst (Free (a, T)) = Free (a, typ_subst_TVars instT T)
wenzelm@16678
   763
          | subst (t as Var (xi, T)) =
haftmann@17271
   764
              (case AList.lookup (op =) inst xi of
wenzelm@16678
   765
                NONE => Var (xi, typ_subst_TVars instT T)
wenzelm@16678
   766
              | SOME t => t)
wenzelm@16678
   767
          | subst (t as Bound _) = t
wenzelm@16678
   768
          | subst (Abs (a, T, t)) = Abs (a, typ_subst_TVars instT T, subst t)
wenzelm@16678
   769
          | subst (t $ u) = subst t $ subst u;
wenzelm@16678
   770
      in subst tm end;
clasohm@0
   771
wenzelm@25050
   772
fun close_schematic_term t =
wenzelm@25050
   773
  let
wenzelm@25050
   774
    val extra_types = map (fn v => Const ("TYPE", itselfT (TVar v))) (hidden_polymorphism t);
wenzelm@25050
   775
    val extra_terms = map Var (rev (add_vars t []));
wenzelm@25050
   776
  in fold_rev lambda (extra_types @ extra_terms) t end;
wenzelm@25050
   777
wenzelm@25050
   778
clasohm@0
   779
paulson@15573
   780
(** Identifying first-order terms **)
paulson@15573
   781
wenzelm@20199
   782
(*Differs from proofterm/is_fun in its treatment of TVar*)
wenzelm@29256
   783
fun is_funtype (Type ("fun", [_, _])) = true
wenzelm@20199
   784
  | is_funtype _ = false;
wenzelm@20199
   785
paulson@15573
   786
(*Argument Ts is a reverse list of binder types, needed if term t contains Bound vars*)
wenzelm@29256
   787
fun has_not_funtype Ts t = not (is_funtype (fastype_of1 (Ts, t)));
paulson@15573
   788
wenzelm@16537
   789
(*First order means in all terms of the form f(t1,...,tn) no argument has a
paulson@16589
   790
  function type. The supplied quantifiers are excluded: their argument always
paulson@16589
   791
  has a function type through a recursive call into its body.*)
wenzelm@16667
   792
fun is_first_order quants =
paulson@16589
   793
  let fun first_order1 Ts (Abs (_,T,body)) = first_order1 (T::Ts) body
wenzelm@16667
   794
        | first_order1 Ts (Const(q,_) $ Abs(a,T,body)) =
wenzelm@20664
   795
            member (op =) quants q  andalso   (*it is a known quantifier*)
paulson@16589
   796
            not (is_funtype T)   andalso first_order1 (T::Ts) body
wenzelm@16667
   797
        | first_order1 Ts t =
wenzelm@16667
   798
            case strip_comb t of
wenzelm@16667
   799
                 (Var _, ts) => forall (first_order1 Ts andf has_not_funtype Ts) ts
wenzelm@16667
   800
               | (Free _, ts) => forall (first_order1 Ts andf has_not_funtype Ts) ts
wenzelm@16667
   801
               | (Const _, ts) => forall (first_order1 Ts andf has_not_funtype Ts) ts
wenzelm@16667
   802
               | (Bound _, ts) => forall (first_order1 Ts andf has_not_funtype Ts) ts
wenzelm@16667
   803
               | (Abs _, ts) => false (*not in beta-normal form*)
wenzelm@16667
   804
               | _ => error "first_order: unexpected case"
paulson@16589
   805
    in  first_order1 []  end;
paulson@15573
   806
wenzelm@16710
   807
wenzelm@16990
   808
(* maximum index of typs and terms *)
clasohm@0
   809
wenzelm@16710
   810
fun maxidx_typ (TVar ((_, j), _)) i = Int.max (i, j)
wenzelm@16710
   811
  | maxidx_typ (Type (_, Ts)) i = maxidx_typs Ts i
wenzelm@16710
   812
  | maxidx_typ (TFree _) i = i
wenzelm@16710
   813
and maxidx_typs [] i = i
wenzelm@16710
   814
  | maxidx_typs (T :: Ts) i = maxidx_typs Ts (maxidx_typ T i);
clasohm@0
   815
wenzelm@16710
   816
fun maxidx_term (Var ((_, j), T)) i = maxidx_typ T (Int.max (i, j))
wenzelm@16710
   817
  | maxidx_term (Const (_, T)) i = maxidx_typ T i
wenzelm@16710
   818
  | maxidx_term (Free (_, T)) i = maxidx_typ T i
wenzelm@16710
   819
  | maxidx_term (Bound _) i = i
wenzelm@16710
   820
  | maxidx_term (Abs (_, T, t)) i = maxidx_term t (maxidx_typ T i)
wenzelm@16710
   821
  | maxidx_term (t $ u) i = maxidx_term u (maxidx_term t i);
clasohm@0
   822
wenzelm@16710
   823
fun maxidx_of_typ T = maxidx_typ T ~1;
wenzelm@16710
   824
fun maxidx_of_typs Ts = maxidx_typs Ts ~1;
wenzelm@16710
   825
fun maxidx_of_term t = maxidx_term t ~1;
berghofe@13665
   826
clasohm@0
   827
clasohm@0
   828
wenzelm@29270
   829
(** misc syntax operations **)
clasohm@0
   830
wenzelm@19909
   831
(* substructure *)
wenzelm@4017
   832
wenzelm@19909
   833
fun exists_subtype P =
wenzelm@19909
   834
  let
wenzelm@19909
   835
    fun ex ty = P ty orelse
wenzelm@19909
   836
      (case ty of Type (_, Ts) => exists ex Ts | _ => false);
wenzelm@19909
   837
  in ex end;
nipkow@13646
   838
wenzelm@20531
   839
fun exists_type P =
wenzelm@20531
   840
  let
wenzelm@20531
   841
    fun ex (Const (_, T)) = P T
wenzelm@20531
   842
      | ex (Free (_, T)) = P T
wenzelm@20531
   843
      | ex (Var (_, T)) = P T
wenzelm@20531
   844
      | ex (Bound _) = false
wenzelm@20531
   845
      | ex (Abs (_, T, t)) = P T orelse ex t
wenzelm@20531
   846
      | ex (t $ u) = ex t orelse ex u;
wenzelm@20531
   847
  in ex end;
wenzelm@20531
   848
wenzelm@16943
   849
fun exists_subterm P =
wenzelm@16943
   850
  let
wenzelm@16943
   851
    fun ex tm = P tm orelse
wenzelm@16943
   852
      (case tm of
wenzelm@16943
   853
        t $ u => ex t orelse ex u
wenzelm@16943
   854
      | Abs (_, _, t) => ex t
wenzelm@16943
   855
      | _ => false);
wenzelm@16943
   856
  in ex end;
obua@16108
   857
wenzelm@29270
   858
fun exists_Const P = exists_subterm (fn Const c => P c | _ => false);
wenzelm@29270
   859
wenzelm@24671
   860
fun has_abs (Abs _) = true
wenzelm@24671
   861
  | has_abs (t $ u) = has_abs t orelse has_abs u
wenzelm@24671
   862
  | has_abs _ = false;
wenzelm@24671
   863
wenzelm@24671
   864
wenzelm@20199
   865
(* dest abstraction *)
clasohm@0
   866
wenzelm@16678
   867
fun dest_abs (x, T, body) =
wenzelm@16678
   868
  let
wenzelm@16678
   869
    fun name_clash (Free (y, _)) = (x = y)
wenzelm@16678
   870
      | name_clash (t $ u) = name_clash t orelse name_clash u
wenzelm@16678
   871
      | name_clash (Abs (_, _, t)) = name_clash t
wenzelm@16678
   872
      | name_clash _ = false;
wenzelm@16678
   873
  in
wenzelm@27335
   874
    if name_clash body then dest_abs (Name.variant [x] x, T, body)    (*potentially slow*)
wenzelm@16678
   875
    else (x, subst_bound (Free (x, T), body))
wenzelm@16678
   876
  end;
wenzelm@16678
   877
wenzelm@20160
   878
wenzelm@20160
   879
(* renaming variables *)
clasohm@0
   880
wenzelm@24762
   881
val declare_typ_names = fold_atyps (fn TFree (a, _) => Name.declare a | _ => I);
wenzelm@24762
   882
wenzelm@20239
   883
fun declare_term_names tm =
wenzelm@20239
   884
  fold_aterms
wenzelm@20239
   885
    (fn Const (a, _) => Name.declare (NameSpace.base a)
wenzelm@20239
   886
      | Free (a, _) => Name.declare a
wenzelm@20239
   887
      | _ => I) tm #>
wenzelm@24762
   888
  fold_types declare_typ_names tm;
wenzelm@20239
   889
wenzelm@20160
   890
fun variant_frees t frees =
wenzelm@20160
   891
  fst (Name.variants (map fst frees) (declare_term_names t Name.context)) ~~ map snd frees;
wenzelm@20160
   892
wenzelm@20160
   893
fun rename_wrt_term t frees = rev (variant_frees t frees);  (*reversed result!*)
clasohm@1364
   894
paulson@1417
   895
wenzelm@9536
   896
(* dummy patterns *)
wenzelm@9536
   897
wenzelm@9536
   898
val dummy_patternN = "dummy_pattern";
wenzelm@9536
   899
wenzelm@18253
   900
fun dummy_pattern T = Const (dummy_patternN, T);
wenzelm@18253
   901
wenzelm@9536
   902
fun is_dummy_pattern (Const ("dummy_pattern", _)) = true
wenzelm@9536
   903
  | is_dummy_pattern _ = false;
wenzelm@9536
   904
wenzelm@9536
   905
fun no_dummy_patterns tm =
haftmann@16787
   906
  if not (fold_aterms (fn t => fn b => b orelse is_dummy_pattern t) tm false) then tm
wenzelm@9536
   907
  else raise TERM ("Illegal occurrence of '_' dummy pattern", [tm]);
wenzelm@9536
   908
wenzelm@24733
   909
fun free_dummy_patterns (Const ("dummy_pattern", T)) used =
wenzelm@24850
   910
      let val [x] = Name.invents used Name.uu 1
wenzelm@24733
   911
      in (Free (Name.internal x, T), Name.declare x used) end
wenzelm@24733
   912
  | free_dummy_patterns (Abs (x, T, b)) used =
wenzelm@24733
   913
      let val (b', used') = free_dummy_patterns b used
wenzelm@24733
   914
      in (Abs (x, T, b'), used') end
wenzelm@24733
   915
  | free_dummy_patterns (t $ u) used =
wenzelm@24733
   916
      let
wenzelm@24733
   917
        val (t', used') = free_dummy_patterns t used;
wenzelm@24733
   918
        val (u', used'') = free_dummy_patterns u used';
wenzelm@24733
   919
      in (t' $ u', used'') end
wenzelm@24733
   920
  | free_dummy_patterns a used = (a, used);
wenzelm@24733
   921
wenzelm@24762
   922
fun replace_dummy Ts (Const ("dummy_pattern", T)) i =
wenzelm@24762
   923
      (list_comb (Var (("_dummy_", i), Ts ---> T), map Bound (0 upto length Ts - 1)), i + 1)
wenzelm@24762
   924
  | replace_dummy Ts (Abs (x, T, t)) i =
wenzelm@24762
   925
      let val (t', i') = replace_dummy (T :: Ts) t i
wenzelm@24762
   926
      in (Abs (x, T, t'), i') end
wenzelm@24762
   927
  | replace_dummy Ts (t $ u) i =
wenzelm@24762
   928
      let
wenzelm@24762
   929
        val (t', i') = replace_dummy Ts t i;
wenzelm@24762
   930
        val (u', i'') = replace_dummy Ts u i';
wenzelm@24762
   931
      in (t' $ u', i'') end
wenzelm@24762
   932
  | replace_dummy _ a i = (a, i);
wenzelm@11903
   933
wenzelm@11903
   934
val replace_dummy_patterns = replace_dummy [];
wenzelm@9536
   935
wenzelm@10552
   936
fun is_replaced_dummy_pattern ("_dummy_", _) = true
wenzelm@10552
   937
  | is_replaced_dummy_pattern _ = false;
wenzelm@9536
   938
wenzelm@16035
   939
fun show_dummy_patterns (Var (("_dummy_", _), T)) = Const ("dummy_pattern", T)
wenzelm@16035
   940
  | show_dummy_patterns (t $ u) = show_dummy_patterns t $ show_dummy_patterns u
wenzelm@16035
   941
  | show_dummy_patterns (Abs (x, T, t)) = Abs (x, T, show_dummy_patterns t)
wenzelm@16035
   942
  | show_dummy_patterns a = a;
wenzelm@16035
   943
wenzelm@13484
   944
wenzelm@20100
   945
(* display variables *)
wenzelm@20100
   946
wenzelm@15986
   947
val show_question_marks = ref true;
berghofe@15472
   948
wenzelm@14786
   949
fun string_of_vname (x, i) =
wenzelm@14786
   950
  let
wenzelm@15986
   951
    val question_mark = if ! show_question_marks then "?" else "";
wenzelm@15986
   952
    val idx = string_of_int i;
wenzelm@15986
   953
    val dot =
wenzelm@15986
   954
      (case rev (Symbol.explode x) of
wenzelm@15986
   955
        _ :: "\\<^isub>" :: _ => false
wenzelm@15986
   956
      | _ :: "\\<^isup>" :: _ => false
wenzelm@15986
   957
      | c :: _ => Symbol.is_digit c
wenzelm@15986
   958
      | _ => true);
wenzelm@14786
   959
  in
wenzelm@15986
   960
    if dot then question_mark ^ x ^ "." ^ idx
wenzelm@15986
   961
    else if i <> 0 then question_mark ^ x ^ idx
wenzelm@15986
   962
    else question_mark ^ x
wenzelm@14786
   963
  end;
wenzelm@14786
   964
wenzelm@14786
   965
fun string_of_vname' (x, ~1) = x
wenzelm@14786
   966
  | string_of_vname' xi = string_of_vname xi;
wenzelm@14786
   967
clasohm@1364
   968
end;
clasohm@1364
   969
wenzelm@4444
   970
structure BasicTerm: BASIC_TERM = Term;
wenzelm@4444
   971
open BasicTerm;