Isabelle NEWS -- history of user-relevant changes

=================================================

(Note: Isabelle/jEdit shows a tree-view of the NEWS file in Sidekick.)

New in this Isabelle version

----------------------------

*** General ***

* Embedded content (e.g. the inner syntax of types, terms, props) may be

delimited uniformly via cartouches. This works better than old-fashioned

quotes when sub-languages are nested.

* Type-inference improves sorts of newly introduced type variables for

the object-logic, using its base sort (i.e. HOL.type for Isabelle/HOL).

Thus terms like "f x" or "\<And>x. P x" without any further syntactic context

produce x::'a::type in HOL instead of x::'a::{} in Pure. Rare

INCOMPATIBILITY, need to provide explicit type constraints for Pure

types where this is really intended.

* Simplified outer syntax: uniform category "name" includes long

identifiers. Former "xname" / "nameref" / "name reference" has been

discontinued.

* Mixfix annotations support general block properties, with syntax

"(\<open>x=a y=b z \<dots>\<close>". Notable property names are "indent", "consistent",

"unbreakable", "markup". The existing notation "(DIGITS" is equivalent

to "(\<open>indent=DIGITS\<close>". The former notation "(00" for unbreakable blocks

is superseded by "(\<open>unbreabable\<close>" --- rare INCOMPATIBILITY.

* New symbol \<circle>, e.g. for temporal operator.

* Old 'header' command is no longer supported (legacy since

Isabelle2015).

* Command 'bundle' provides a local theory target to define a bundle

from the body of specification commands (such as 'declare',

'declaration', 'notation', 'lemmas', 'lemma'). For example:

bundle foo

begin

  declare a [simp]

  declare b [intro]

end

* Command 'unbundle' is like 'include', but works within a local theory

context. Unlike "context includes ... begin", the effect of 'unbundle'

on the target context persists, until different declarations are given.

* Proof method "blast" is more robust wrt. corner cases of Pure

statements without object-logic judgment.

*** Prover IDE -- Isabelle/Scala/jEdit ***

* Cartouche abbreviations work both for " and ` to accomodate typical

situations where old ASCII notation may be updated.

* IDE support for the Isabelle/Pure bootstrap process, with the

following independent stages:

  src/Pure/ROOT0.ML

  src/Pure/ROOT.ML

  src/Pure/Pure.thy

  src/Pure/ML_Bootstrap.thy

The ML ROOT files act like quasi-theories in the context of theory

ML_Bootstrap: this allows continuous checking of all loaded ML files.

The theory files are presented with a modified header to import Pure

from the running Isabelle instance. Results from changed versions of

each stage are *not* propagated to the next stage, and isolated from the

actual Isabelle/Pure that runs the IDE itself. The sequential

dependencies of the above files are only observed for batch build.

* Highlighting of entity def/ref positions wrt. cursor.

* Action "isabelle.select-entity" (shortcut CS+ENTER) selects all

occurences of the formal entity at the caret position. This facilitates

systematic renaming.

* Document markup works across multiple Isar commands, e.g. the results

established at the end of a proof are properly identified in the theorem

statement.

*** Isar ***

* The defining position of a literal fact \<open>prop\<close> is maintained more

carefully, and made accessible as hyperlink in the Prover IDE.

* Commands 'finally' and 'ultimately' used to expose the result as

literal fact: this accidental behaviour has been discontinued. Rare

INCOMPATIBILITY, use more explicit means to refer to facts in Isar.

* Command 'axiomatization' has become more restrictive to correspond

better to internal axioms as singleton facts with mandatory name. Minor

INCOMPATIBILITY.

* Many specification elements support structured statements with 'if' /

'for' eigen-context, e.g. 'axiomatization', 'abbreviation',

'definition', 'inductive', 'function'.

* Toplevel theorem statements support eigen-context notation with 'if' /

'for' (in postfix), which corresponds to 'assumes' / 'fixes' in the

traditional long statement form (in prefix). Local premises are called

"that" or "assms", respectively. Empty premises are *not* bound in the

context: INCOMPATIBILITY.

* Command 'define' introduces a local (non-polymorphic) definition, with

optional abstraction over local parameters. The syntax resembles

'definition' and 'obtain'. It fits better into the Isar language than

old 'def', which is now a legacy feature.

* Command 'obtain' supports structured statements with 'if' / 'for'

context.

* Command '\<proof>' is an alias for 'sorry', with different

typesetting. E.g. to produce proof holes in examples and documentation.

* The old proof method "default" has been removed (legacy since

Isabelle2016). INCOMPATIBILITY, use "standard" instead.

* Proof methods may refer to the main facts via the dynamic fact

"method_facts". This is particularly useful for Eisbach method

definitions.

* Eisbach provides method "use" to modify the main facts of a given

method expression, e.g.

  (use facts in simp)

  (use facts in \<open>simp add: ...\<close>)

*** Pure ***

* Code generator: config option "code_timing" triggers measurements of

different phases of code generation. See src/HOL/ex/Code_Timing.thy for

examples.

* Code generator: implicits in Scala (stemming from type class instances)

are generated into companion object of corresponding type class, to resolve

some situations where ambiguities may occur.

*** HOL ***

* Former locale lifting_syntax is now a bundle, which is easier to

include in a local context or theorem statement, e.g. "context includes

lifting_syntax begin ... end". Minor INCOMPATIBILITY.

* Code generation for scala: ambiguous implicts in class diagrams

are spelt out explicitly.

* Abstract locales semigroup, abel_semigroup, semilattice,

semilattice_neutr, ordering, ordering_top, semilattice_order,

semilattice_neutr_order, comm_monoid_set, semilattice_set,

semilattice_neutr_set, semilattice_order_set, semilattice_order_neutr_set

monoid_list, comm_monoid_list, comm_monoid_list_set, comm_monoid_mset,

comm_monoid_fun use boldified syntax uniformly that does not clash

with corresponding global syntax.  INCOMPATIBILITY.

* Conventional syntax "%(). t" for unit abstractions.  Slight syntactic

INCOMPATIBILITY.

* Command 'code_reflect' accepts empty constructor lists for datatypes,

which renders those abstract effectively.

* Command 'export_code' checks given constants for abstraction violations:

a small guarantee that given constants specify a safe interface for the

generated code.

* Probability/Random_Permutations.thy contains some theory about 

choosing a permutation of a set uniformly at random and folding over a 

list in random order.

* Probability/SPMF formalises discrete subprobability distributions.

* Library/FinFun.thy: bundles "finfun_syntax" and "no_finfun_syntax"

allow to control optional syntax in local contexts; this supersedes

former Library/FinFun_Syntax.thy. INCOMPATIBILITY, e.g. use "unbundle

finfun_syntax" to imitate import of "~~/src/HOL/Library/FinFun_Syntax".

* Library/Set_Permutations.thy (executably) defines the set of 

permutations of a set, i.e. the set of all lists that contain every 

element of the carrier set exactly once.

* Static evaluators (Code_Evaluation.static_* in Isabelle/ML) rely on

explicitly provided auxiliary definitions for required type class

dictionaries rather than half-working magic.  INCOMPATIBILITY, see

the tutorial on code generation for details.

* New abbreviations for negated existence (but not bounded existence):

  \<nexists>x. P x \<equiv> \<not> (\<exists>x. P x)

  \<nexists>!x. P x \<equiv> \<not> (\<exists>!x. P x)

* The print mode "HOL" for ASCII syntax of binders "!", "?", "?!", "@"

has been removed for output. It is retained for input only, until it is

eliminated altogether.

* Sledgehammer:

  - Produce syntactically correct Vampire 4.0 problem files.

* (Co)datatype package:

  - New commands for defining corecursive functions and reasoning about

    them in "~~/src/HOL/Library/BNF_Corec.thy": 'corec', 'corecursive',

    'friend_of_corec', and 'corecursion_upto'; and 'corec_unique' proof

    method. See 'isabelle doc corec'.

  - The predicator :: ('a => bool) => 'a F => bool is now a first-class

    citizen in bounded natural functors

  - 'primrec' now allows nested calls through the predicator in addition

    to the map function.

  - 'bnf' automatically discharges reflexive proof obligations

  - 'bnf' outputs a slightly modified proof obligation expressing rel in

       terms of map and set

       (not giving a specification for rel makes this one reflexive)

  - 'bnf' outputs a new proof obligation expressing pred in terms of set

       (not giving a specification for pred makes this one reflexive)

    INCOMPATIBILITY: manual 'bnf' declarations may need adjustment

  - Renamed lemmas:

      rel_prod_apply ~> rel_prod_inject

      pred_prod_apply ~> pred_prod_inject

    INCOMPATIBILITY.

  - The "size" plugin has been made compatible again with locales.

* Removed obsolete theorem nat_less_cases. INCOMPATIBILITY, use

linorder_cases instead.

* Renamed split_if -> if_split and split_if_asm -> if_split_asm to

resemble the f.split naming convention, INCOMPATIBILITY.

* Characters (type char) are modelled as finite algebraic type

corresponding to {0..255}.

  - Logical representation:

    * 0 is instantiated to the ASCII zero character.

    * All other characters are represented as "Char n"

      with n being a raw numeral expression less than 256.

    * Expressions of the form "Char n" with n greater than 255

      are non-canonical.

  - Printing and parsing:

    * Printable characters are printed and parsed as "CHR ''\<dots>''"

      (as before).

    * The ASCII zero character is printed and parsed as "0".

    * All other canonical characters are printed as "CHR 0xXX"

      with XX being the hexadecimal character code.  "CHR n"

      is parsable for every numeral expression n.

    * Non-canonical characters have no special syntax and are

      printed as their logical representation.

  - Explicit conversions from and to the natural numbers are

    provided as char_of_nat, nat_of_char (as before).

  - The auxiliary nibble type has been discontinued.

INCOMPATIBILITY.

* Multiset membership is now expressed using set_mset rather than count.

  - Expressions "count M a > 0" and similar simplify to membership

    by default.

  - Converting between "count M a = 0" and non-membership happens using

    equations count_eq_zero_iff and not_in_iff.

  - Rules count_inI and in_countE obtain facts of the form

    "count M a = n" from membership.

  - Rules count_in_diffI and in_diff_countE obtain facts of the form

    "count M a = n + count N a" from membership on difference sets.

INCOMPATIBILITY.

* The names of multiset theorems have been normalised to distinguish which

  ordering the theorems are about

    mset_less_eqI ~> mset_subset_eqI

    mset_less_insertD ~> mset_subset_insertD

    mset_less_eq_count ~> mset_subset_eq_count

    mset_less_diff_self ~> mset_subset_diff_self

    mset_le_exists_conv ~> mset_subset_eq_exists_conv

    mset_le_mono_add_right_cancel ~> mset_subset_eq_mono_add_right_cancel

    mset_le_mono_add_left_cancel ~> mset_subset_eq_mono_add_left_cancel

    mset_le_mono_add ~> mset_subset_eq_mono_add

    mset_le_add_left ~> mset_subset_eq_add_left

    mset_le_add_right ~> mset_subset_eq_add_right

    mset_le_single ~> mset_subset_eq_single

    mset_le_multiset_union_diff_commute ~> mset_subset_eq_multiset_union_diff_commute

    diff_le_self ~> diff_subset_eq_self

    mset_leD ~> mset_subset_eqD

    mset_lessD ~> mset_subsetD

    mset_le_insertD ~> mset_subset_eq_insertD

    mset_less_of_empty ~> mset_subset_of_empty

    le_empty ~> subset_eq_empty

    mset_less_add_bothsides ~> mset_subset_add_bothsides

    mset_less_empty_nonempty ~> mset_subset_empty_nonempty

    mset_less_size ~> mset_subset_size

    wf_less_mset_rel ~> wf_subset_mset_rel

    count_le_replicate_mset_le ~> count_le_replicate_mset_subset_eq

    mset_remdups_le ~> mset_remdups_subset_eq

    ms_lesseq_impl ~> subset_eq_mset_impl

  Some functions have been renamed:

    ms_lesseq_impl -> subset_eq_mset_impl

* Compound constants INFIMUM and SUPREMUM are mere abbreviations now.

INCOMPATIBILITY.

* More complex analysis including Cauchy's inequality, Liouville theorem,

open mapping theorem, maximum modulus principle, Residue theorem, Schwarz Lemma.

* Theory of polyhedra: faces, extreme points, polytopes, and the Krein–Milman

Minkowski theorem.

* "Gcd (f ` A)" and "Lcm (f ` A)" are printed with optional

comprehension-like syntax analogously to "Inf (f ` A)" and "Sup (f ` A)".

* Class semiring_Lcd merged into semiring_Gcd.  INCOMPATIBILITY.

* The type class ordered_comm_monoid_add is now called

ordered_cancel_comm_monoid_add. A new type class ordered_comm_monoid_add is

introduced as the combination of ordered_ab_semigroup_add + comm_monoid_add.

INCOMPATIBILITY.

* Introduced the type classes canonically_ordered_comm_monoid_add and dioid.

* Added topological_monoid

* Library/Complete_Partial_Order2.thy provides reasoning support for

proofs about monotonicity and continuity in chain-complete partial

orders and about admissibility conditions for fixpoint inductions.

* Library/Polynomial.thy contains also derivation of polynomials

but not gcd/lcm on polynomials over fields.  This has been moved

to a separate theory Library/Polynomial_GCD_euclidean.thy, to

pave way for a possible future different type class instantiation

for polynomials over factorial rings.  INCOMPATIBILITY.

* Library/Sublist.thy: added function "prefixes" and renamed

  prefixeq -> prefix

  prefix -> strict_prefix

  suffixeq -> suffix

  suffix -> strict_suffix

  Added theory of longest common prefixes.

* Dropped various legacy fact bindings, whose replacements are often

of a more general type also:

  lcm_left_commute_nat ~> lcm.left_commute

  lcm_left_commute_int ~> lcm.left_commute

  gcd_left_commute_nat ~> gcd.left_commute

  gcd_left_commute_int ~> gcd.left_commute

  gcd_greatest_iff_nat ~> gcd_greatest_iff

  gcd_greatest_iff_int ~> gcd_greatest_iff

  coprime_dvd_mult_nat ~> coprime_dvd_mult

  coprime_dvd_mult_int ~> coprime_dvd_mult

  zpower_numeral_even ~> power_numeral_even

  gcd_mult_cancel_nat ~> gcd_mult_cancel

  gcd_mult_cancel_int ~> gcd_mult_cancel

  div_gcd_coprime_nat ~> div_gcd_coprime

  div_gcd_coprime_int ~> div_gcd_coprime

  zpower_numeral_odd ~> power_numeral_odd

  zero_less_int_conv ~> of_nat_0_less_iff

  gcd_greatest_nat ~> gcd_greatest

  gcd_greatest_int ~> gcd_greatest

  coprime_mult_nat ~> coprime_mult

  coprime_mult_int ~> coprime_mult

  lcm_commute_nat ~> lcm.commute

  lcm_commute_int ~> lcm.commute

  int_less_0_conv ~> of_nat_less_0_iff

  gcd_commute_nat ~> gcd.commute

  gcd_commute_int ~> gcd.commute

  Gcd_insert_nat ~> Gcd_insert

  Gcd_insert_int ~> Gcd_insert

  of_int_int_eq ~> of_int_of_nat_eq

  lcm_least_nat ~> lcm_least

  lcm_least_int ~> lcm_least

  lcm_assoc_nat ~> lcm.assoc

  lcm_assoc_int ~> lcm.assoc

  int_le_0_conv ~> of_nat_le_0_iff

  int_eq_0_conv ~> of_nat_eq_0_iff

  Gcd_empty_nat ~> Gcd_empty

  Gcd_empty_int ~> Gcd_empty

  gcd_assoc_nat ~> gcd.assoc

  gcd_assoc_int ~> gcd.assoc

  zero_zle_int ~> of_nat_0_le_iff

  lcm_dvd2_nat ~> dvd_lcm2

  lcm_dvd2_int ~> dvd_lcm2

  lcm_dvd1_nat ~> dvd_lcm1

  lcm_dvd1_int ~> dvd_lcm1

  gcd_zero_nat ~> gcd_eq_0_iff

  gcd_zero_int ~> gcd_eq_0_iff

  gcd_dvd2_nat ~> gcd_dvd2

  gcd_dvd2_int ~> gcd_dvd2

  gcd_dvd1_nat ~> gcd_dvd1

  gcd_dvd1_int ~> gcd_dvd1

  int_numeral ~> of_nat_numeral

  lcm_ac_nat ~> ac_simps

  lcm_ac_int ~> ac_simps

  gcd_ac_nat ~> ac_simps

  gcd_ac_int ~> ac_simps

  abs_int_eq ~> abs_of_nat

  zless_int ~> of_nat_less_iff

  zdiff_int ~> of_nat_diff

  zadd_int ~> of_nat_add

  int_mult ~> of_nat_mult

  int_Suc ~> of_nat_Suc

  inj_int ~> inj_of_nat

  int_1 ~> of_nat_1

  int_0 ~> of_nat_0

  Lcm_empty_nat ~> Lcm_empty

  Lcm_empty_int ~> Lcm_empty

  Lcm_insert_nat ~> Lcm_insert

  Lcm_insert_int ~> Lcm_insert

  comp_fun_idem_gcd_nat ~> comp_fun_idem_gcd

  comp_fun_idem_gcd_int ~> comp_fun_idem_gcd

  comp_fun_idem_lcm_nat ~> comp_fun_idem_lcm

  comp_fun_idem_lcm_int ~> comp_fun_idem_lcm

  Lcm_eq_0 ~> Lcm_eq_0_I

  Lcm0_iff ~> Lcm_0_iff

  Lcm_dvd_int ~> Lcm_least

  divides_mult_nat ~> divides_mult

  divides_mult_int ~> divides_mult

  lcm_0_nat ~> lcm_0_right

  lcm_0_int ~> lcm_0_right

  lcm_0_left_nat ~> lcm_0_left

  lcm_0_left_int ~> lcm_0_left

  dvd_gcd_D1_nat ~> dvd_gcdD1

  dvd_gcd_D1_int ~> dvd_gcdD1

  dvd_gcd_D2_nat ~> dvd_gcdD2

  dvd_gcd_D2_int ~> dvd_gcdD2

  coprime_dvd_mult_iff_nat ~> coprime_dvd_mult_iff

  coprime_dvd_mult_iff_int ~> coprime_dvd_mult_iff

  realpow_minus_mult ~> power_minus_mult

  realpow_Suc_le_self ~> power_Suc_le_self

  dvd_Gcd, dvd_Gcd_nat, dvd_Gcd_int removed in favour of Gcd_greatest

INCOMPATIBILITY.

* Session HOL-NSA has been renamed to HOL-Nonstandard_Analysis.

* In HOL-Probability the type of emeasure and nn_integral was changed

from ereal to ennreal:

  emeasure :: 'a measure => 'a set => ennreal

  nn_integral :: 'a measure => ('a => ennreal) => ennreal

INCOMPATIBILITY.

*** ML ***

* Integer.gcd and Integer.lcm use efficient operations from the Poly/ML

library (notably for big integers). Subtle change of semantics:

Integer.gcd and Integer.lcm both normalize the sign, results are never

negative. This coincides with the definitions in HOL/GCD.thy.

INCOMPATIBILITY.

* Structure Rat for rational numbers is now an integral part of

Isabelle/ML, with special notation @int/nat or @int for numerals (an

abbreviation for antiquotation @{Pure.rat argument}) and ML pretty

printing. Standard operations on type Rat.rat are provided via ad-hoc

overloading of + - * / < <= > >= ~ abs. INCOMPATIBILITY, need to

use + instead of +/ etc. Moreover, exception Rat.DIVZERO has been

superseded by General.Div.

* The ML function "ML" provides easy access to run-time compilation.

This is particularly useful for conditional compilation, without

requiring separate files.

* Low-level ML system structures (like PolyML and RunCall) are no longer

exposed to Isabelle/ML user-space. Potential INCOMPATIBILITY.

* Antiquotation @{make_string} is available during Pure bootstrap --

with approximative output quality.

* Option ML_exception_debugger controls detailed exception trace via the

Poly/ML debugger. Relevant ML modules need to be compiled beforehand

with ML_file_debug, or with ML_file and option ML_debugger enabled. Note

debugger information requires consirable time and space: main

Isabelle/HOL with full debugger support may need ML_system_64.

* Local_Theory.restore has been renamed to Local_Theory.reset to

emphasize its disruptive impact on the cumulative context, notably the

scope of 'private' or 'qualified' names. Note that Local_Theory.reset is

only appropriate when targets are managed, e.g. starting from a global

theory and returning to it. Regular definitional packages should use

balanced blocks of Local_Theory.open_target versus

Local_Theory.close_target instead. Rare INCOMPATIBILITY.

* Structure TimeLimit (originally from the SML/NJ library) has been

replaced by structure Timeout, with slightly different signature.

INCOMPATIBILITY.

* Discontinued cd and pwd operations, which are not well-defined in a

multi-threaded environment. Note that files are usually located

relatively to the master directory of a theory (see also

File.full_path). Potential INCOMPATIBILITY.

* Binding.empty_atts supersedes Thm.empty_binding and

Attrib.empty_binding. Minor INCOMPATIBILITY.

*** System ***

* Many Isabelle tools that require a Java runtime system refer to the

settings ISABELLE_TOOL_JAVA_OPTIONS32 / ISABELLE_TOOL_JAVA_OPTIONS64,

depending on the underlying platform. The settings for "isabelle build"

ISABELLE_BUILD_JAVA_OPTIONS32 / ISABELLE_BUILD_JAVA_OPTIONS64 have been

discontinued. Potential INCOMPATIBILITY.

* The Isabelle system environment always ensures that the main

executables are found within the shell search $PATH: "isabelle" and

"isabelle_scala_script".

* Isabelle tools may consist of .scala files: the Scala compiler is

invoked on the spot. The source needs to define some object that extends

Isabelle_Tool.Body.

* The Isabelle ML process is now managed directly by Isabelle/Scala, and

shell scripts merely provide optional command-line access. In

particular:

  . Scala module ML_Process to connect to the raw ML process,

    with interaction via stdin/stdout/stderr or in batch mode;

  . command-line tool "isabelle console" as interactive wrapper;

  . command-line tool "isabelle process" as batch mode wrapper.

* The executable "isabelle_process" has been discontinued. Tools and

prover front-ends should use ML_Process or Isabelle_Process in

Isabelle/Scala. INCOMPATIBILITY.

* New command-line tool "isabelle process" supports ML evaluation of

literal expressions (option -e) or files (option -f) in the context of a

given heap image. Errors lead to premature exit of the ML process with

return code 1.

* Command-line tool "isabelle console" provides option -r to help to

bootstrapping Isabelle/Pure interactively.

* Command-line tool "isabelle yxml" has been discontinued.

INCOMPATIBILITY, use operations from the modules "XML" and "YXML" in

Isabelle/ML or Isabelle/Scala.

* File.bash_string, File.bash_path etc. represent Isabelle/ML and

Isabelle/Scala strings authentically within GNU bash. This is useful to

produce robust shell scripts under program control, without worrying

about spaces or special characters. Note that user output works via

Path.print (ML) or Path.toString (Scala). INCOMPATIBILITY, the old (and

less versatile) operations File.shell_quote, File.shell_path etc. have

been discontinued.

* SML/NJ and old versions of Poly/ML are no longer supported.

* Poly/ML heaps now follow the hierarchy of sessions, and thus require

much less disk space.

New in Isabelle2016 (February 2016)

-----------------------------------

*** General ***

* Eisbach is now based on Pure instead of HOL. Objects-logics may import

either the theory ~~/src/HOL/Eisbach/Eisbach (for HOL etc.) or

~~/src/HOL/Eisbach/Eisbach_Old_Appl_Syntax (for FOL, ZF etc.). Note that

the HOL-Eisbach session located in ~~/src/HOL/Eisbach/ contains further

examples that do require HOL.

* Better resource usage on all platforms (Linux, Windows, Mac OS X) for

both Isabelle/ML and Isabelle/Scala.  Slightly reduced heap space usage.

* Former "xsymbols" syntax with Isabelle symbols is used by default,

without any special print mode. Important ASCII replacement syntax

remains available under print mode "ASCII", but less important syntax

has been removed (see below).

* Support for more arrow symbols, with rendering in LaTeX and Isabelle

fonts: \<Lleftarrow> \<Rrightarrow> \<longlongleftarrow> \<longlongrightarrow> \<longlonglongleftarrow> \<longlonglongrightarrow>.

* Special notation \<struct> for the first implicit 'structure' in the

context has been discontinued. Rare INCOMPATIBILITY, use explicit

structure name instead, notably in indexed notation with block-subscript

(e.g. \<odot>\<^bsub>A\<^esub>).

* The glyph for \<diamond> in the IsabelleText font now corresponds better to its

counterpart \<box> as quantifier-like symbol. A small diamond is available as

\<diamondop>; the old symbol \<struct> loses this rendering and any special

meaning.

* Syntax for formal comments "-- text" now also supports the symbolic

form "\<comment> text". Command-line tool "isabelle update_cartouches -c" helps

to update old sources.

* Toplevel theorem statements have been simplified as follows:

  theorems             ~>  lemmas

  schematic_lemma      ~>  schematic_goal

  schematic_theorem    ~>  schematic_goal

  schematic_corollary  ~>  schematic_goal

Command-line tool "isabelle update_theorems" updates theory sources

accordingly.

* Toplevel theorem statement 'proposition' is another alias for

'theorem'.

* The old 'defs' command has been removed (legacy since Isabelle2014).

INCOMPATIBILITY, use regular 'definition' instead. Overloaded and/or

deferred definitions require a surrounding 'overloading' block.

*** Prover IDE -- Isabelle/Scala/jEdit ***

* IDE support for the source-level debugger of Poly/ML, to work with

Isabelle/ML and official Standard ML. Option "ML_debugger" and commands

'ML_file_debug', 'ML_file_no_debug', 'SML_file_debug',

'SML_file_no_debug' control compilation of sources with or without

debugging information. The Debugger panel allows to set breakpoints (via

context menu), step through stopped threads, evaluate local ML

expressions etc. At least one Debugger view needs to be active to have

any effect on the running ML program.

* The State panel manages explicit proof state output, with dynamic

auto-update according to cursor movement. Alternatively, the jEdit

action "isabelle.update-state" (shortcut S+ENTER) triggers manual

update.

* The Output panel no longer shows proof state output by default, to

avoid GUI overcrowding. INCOMPATIBILITY, use the State panel instead or

enable option "editor_output_state".

* The text overview column (status of errors, warnings etc.) is updated

asynchronously, leading to much better editor reactivity. Moreover, the

full document node content is taken into account. The width of the

column is scaled according to the main text area font, for improved

visibility.

* The main text area no longer changes its color hue in outdated

situations. The text overview column takes over the role to indicate

unfinished edits in the PIDE pipeline. This avoids flashing text display

due to ad-hoc updates by auxiliary GUI components, such as the State

panel.

* Slightly improved scheduling for urgent print tasks (e.g. command

state output, interactive queries) wrt. long-running background tasks.

* Completion of symbols via prefix of \<name> or \<^name> or \name is

always possible, independently of the language context. It is never

implicit: a popup will show up unconditionally.

* Additional abbreviations for syntactic completion may be specified in

$ISABELLE_HOME/etc/abbrevs and $ISABELLE_HOME_USER/etc/abbrevs, with

support for simple templates using ASCII 007 (bell) as placeholder.

* Symbols \<oplus>, \<Oplus>, \<otimes>, \<Otimes>, \<odot>, \<Odot>, \<ominus>, \<oslash> no longer provide abbreviations for

completion like "+o", "*o", ".o" etc. -- due to conflicts with other

ASCII syntax. INCOMPATIBILITY, use plain backslash-completion or define

suitable abbreviations in $ISABELLE_HOME_USER/etc/abbrevs.

* Action "isabelle-emph" (with keyboard shortcut C+e LEFT) controls

emphasized text style; the effect is visible in document output, not in

the editor.

* Action "isabelle-reset" now uses keyboard shortcut C+e BACK_SPACE,

instead of former C+e LEFT.

* The command-line tool "isabelle jedit" and the isabelle.Main

application wrapper treat the default $USER_HOME/Scratch.thy more

uniformly, and allow the dummy file argument ":" to open an empty buffer

instead.

* New command-line tool "isabelle jedit_client" allows to connect to an

already running Isabelle/jEdit process. This achieves the effect of

single-instance applications seen on common GUI desktops.

* The default look-and-feel for Linux is the traditional "Metal", which

works better with GUI scaling for very high-resolution displays (e.g.

4K). Moreover, it is generally more robust than "Nimbus".

* Update to jedit-5.3.0, with improved GUI scaling and support of

high-resolution displays (e.g. 4K).

* The main Isabelle executable is managed as single-instance Desktop

application uniformly on all platforms: Linux, Windows, Mac OS X.

*** Document preparation ***

* Commands 'paragraph' and 'subparagraph' provide additional section

headings. Thus there are 6 levels of standard headings, as in HTML.

* Command 'text_raw' has been clarified: input text is processed as in

'text' (with antiquotations and control symbols). The key difference is

the lack of the surrounding isabelle markup environment in output.

* Text is structured in paragraphs and nested lists, using notation that

is similar to Markdown. The control symbols for list items are as

follows:

  \<^item>  itemize

  \<^enum>  enumerate

  \<^descr>  description

* There is a new short form for antiquotations with a single argument

that is a cartouche: \<^name>\<open>...\<close> is equivalent to @{name \<open>...\<close>} and

\<open>...\<close> without control symbol is equivalent to @{cartouche \<open>...\<close>}.

\<^name> without following cartouche is equivalent to @{name}. The

standard Isabelle fonts provide glyphs to render important control

symbols, e.g. "\<^verbatim>", "\<^emph>", "\<^bold>".

* Antiquotations @{noindent}, @{smallskip}, @{medskip}, @{bigskip} with

corresponding control symbols \<^noindent>, \<^smallskip>, \<^medskip>, \<^bigskip> specify spacing formally, using

standard LaTeX macros of the same names.

* Antiquotation @{cartouche} in Isabelle/Pure is the same as @{text}.

Consequently, \<open>...\<close> without any decoration prints literal quasi-formal

text. Command-line tool "isabelle update_cartouches -t" helps to update

old sources, by approximative patching of the content of string and

cartouche tokens seen in theory sources.

* The @{text} antiquotation now ignores the antiquotation option

"source". The given text content is output unconditionally, without any

surrounding quotes etc. Subtle INCOMPATIBILITY, put quotes into the

argument where they are really intended, e.g. @{text \<open>"foo"\<close>}. Initial

or terminal spaces are ignored.

* Antiquotations @{emph} and @{bold} output LaTeX source recursively,

adding appropriate text style markup. These may be used in the short

form \<^emph>\<open>...\<close> and \<^bold>\<open>...\<close>.

* Document antiquotation @{footnote} outputs LaTeX source recursively,

marked as \footnote{}. This may be used in the short form \<^footnote>\<open>...\<close>.

* Antiquotation @{verbatim [display]} supports option "indent".

* Antiquotation @{theory_text} prints uninterpreted theory source text

(Isar outer syntax with command keywords etc.). This may be used in the

short form \<^theory_text>\<open>...\<close>. @{theory_text [display]} supports option "indent".

* Antiquotation @{doc ENTRY} provides a reference to the given

documentation, with a hyperlink in the Prover IDE.

* Antiquotations @{command}, @{method}, @{attribute} print checked

entities of the Isar language.

* HTML presentation uses the standard IsabelleText font and Unicode

rendering of Isabelle symbols like Isabelle/Scala/jEdit.  The former

print mode "HTML" loses its special meaning.

*** Isar ***

* Local goals ('have', 'show', 'hence', 'thus') allow structured rule

statements like fixes/assumes/shows in theorem specifications, but the

notation is postfix with keywords 'if' (or 'when') and 'for'. For

example:

  have result: "C x y"

    if "A x" and "B y"

    for x :: 'a and y :: 'a

    <proof>

The local assumptions are bound to the name "that". The result is

exported from context of the statement as usual. The above roughly

corresponds to a raw proof block like this:

  {

    fix x :: 'a and y :: 'a

    assume that: "A x" "B y"

    have "C x y" <proof>

  }

  note result = this

The keyword 'when' may be used instead of 'if', to indicate 'presume'

instead of 'assume' above.

* Assumptions ('assume', 'presume') allow structured rule statements

using 'if' and 'for', similar to 'have' etc. above. For example:

  assume result: "C x y"

    if "A x" and "B y"

    for x :: 'a and y :: 'a

This assumes "\<And>x y::'a. A x \<Longrightarrow> B y \<Longrightarrow> C x y" and produces a general

result as usual: "A ?x \<Longrightarrow> B ?y \<Longrightarrow> C ?x ?y".

Vacuous quantification in assumptions is omitted, i.e. a for-context

only effects propositions according to actual use of variables. For

example:

  assume "A x" and "B y" for x and y

is equivalent to:

  assume "\<And>x. A x" and "\<And>y. B y"

* The meaning of 'show' with Pure rule statements has changed: premises

are treated in the sense of 'assume', instead of 'presume'. This means,

a goal like "\<And>x. A x \<Longrightarrow> B x \<Longrightarrow> C x" can be solved completely as

follows:

  show "\<And>x. A x \<Longrightarrow> B x \<Longrightarrow> C x"

or:

  show "C x" if "A x" "B x" for x

Rare INCOMPATIBILITY, the old behaviour may be recovered as follows:

  show "C x" when "A x" "B x" for x

* New command 'consider' states rules for generalized elimination and

case splitting. This is like a toplevel statement "theorem obtains" used

within a proof body; or like a multi-branch 'obtain' without activation

of the local context elements yet.

* Proof method "cases" allows to specify the rule as first entry of

chained facts.  This is particularly useful with 'consider':

  consider (a) A | (b) B | (c) C <proof>

  then have something

  proof cases

    case a

    then show ?thesis <proof>

  next

    case b

    then show ?thesis <proof>

  next

    case c

    then show ?thesis <proof>

  qed

* Command 'case' allows fact name and attribute specification like this:

  case a: (c xs)

  case a [attributes]: (c xs)

Facts that are introduced by invoking the case context are uniformly

qualified by "a"; the same name is used for the cumulative fact. The old

form "case (c xs) [attributes]" is no longer supported. Rare

INCOMPATIBILITY, need to adapt uses of case facts in exotic situations,

and always put attributes in front.

* The standard proof method of commands 'proof' and '..' is now called

"standard" to make semantically clear what it is; the old name "default"

is still available as legacy for some time. Documentation now explains

'..' more accurately as "by standard" instead of "by rule".

* Nesting of Isar goal structure has been clarified: the context after

the initial backwards refinement is retained for the whole proof, within

all its context sections (as indicated via 'next'). This is e.g.

relevant for 'using', 'including', 'supply':

  have "A \<and> A" if a: A for A

    supply [simp] = a

  proof

    show A by simp

  next

    show A by simp

  qed

* Command 'obtain' binds term abbreviations (via 'is' patterns) in the

proof body as well, abstracted over relevant parameters.

* Improved type-inference for theorem statement 'obtains': separate

parameter scope for of each clause.

* Term abbreviations via 'is' patterns also work for schematic

statements: result is abstracted over unknowns.

* Command 'subgoal' allows to impose some structure on backward

refinements, to avoid proof scripts degenerating into long of 'apply'

sequences. Further explanations and examples are given in the isar-ref

manual.

* Command 'supply' supports fact definitions during goal refinement

('apply' scripts).

* Proof method "goal_cases" turns the current subgoals into cases within

the context; the conclusion is bound to variable ?case in each case. For

example:

lemma "\<And>x. A x \<Longrightarrow> B x \<Longrightarrow> C x"

  and "\<And>y z. U y \<Longrightarrow> V z \<Longrightarrow> W y z"

proof goal_cases

  case (1 x)

  then show ?case using \<open>A x\<close> \<open>B x\<close> sorry

next

  case (2 y z)

  then show ?case using \<open>U y\<close> \<open>V z\<close> sorry

qed

lemma "\<And>x. A x \<Longrightarrow> B x \<Longrightarrow> C x"

  and "\<And>y z. U y \<Longrightarrow> V z \<Longrightarrow> W y z"

proof goal_cases

  case prems: 1

  then show ?case using prems sorry

next

  case prems: 2

  then show ?case using prems sorry

qed

* The undocumented feature of implicit cases goal1, goal2, goal3, etc.

is marked as legacy, and will be removed eventually. The proof method

"goals" achieves a similar effect within regular Isar; often it can be

done more adequately by other means (e.g. 'consider').

* The vacuous fact "TERM x" may be established "by fact" or as `TERM x`

as well, not just "by this" or "." as before.

* Method "sleep" succeeds after a real-time delay (in seconds). This is

occasionally useful for demonstration and testing purposes.

*** Pure ***

* Qualifiers in locale expressions default to mandatory ('!') regardless

of the command. Previously, for 'locale' and 'sublocale' the default was

optional ('?'). The old synatx '!' has been discontinued.

INCOMPATIBILITY, remove '!' and add '?' as required.

* Keyword 'rewrites' identifies rewrite morphisms in interpretation

commands. Previously, the keyword was 'where'. INCOMPATIBILITY.

* More gentle suppression of syntax along locale morphisms while

printing terms. Previously 'abbreviation' and 'notation' declarations

would be suppressed for morphisms except term identity. Now

'abbreviation' is also kept for morphims that only change the involved

parameters, and only 'notation' is suppressed. This can be of great help

when working with complex locale hierarchies, because proof states are

displayed much more succinctly. It also means that only notation needs

to be redeclared if desired, as illustrated by this example:

  locale struct = fixes composition :: "'a => 'a => 'a" (infixl "\<cdot>" 65)

  begin

    definition derived (infixl "\<odot>" 65) where ...

  end

  locale morphism =

    left: struct composition + right: struct composition'

    for composition (infix "\<cdot>" 65) and composition' (infix "\<cdot>''" 65)

  begin

    notation right.derived ("\<odot>''")

  end

* Command 'global_interpretation' issues interpretations into global

theories, with optional rewrite definitions following keyword 'defines'.

* Command 'sublocale' accepts optional rewrite definitions after keyword

'defines'.

* Command 'permanent_interpretation' has been discontinued. Use

'global_interpretation' or 'sublocale' instead. INCOMPATIBILITY.

* Command 'print_definitions' prints dependencies of definitional

specifications. This functionality used to be part of 'print_theory'.

* Configuration option rule_insts_schematic has been discontinued

(intermediate legacy feature in Isabelle2015). INCOMPATIBILITY.

* Abbreviations in type classes now carry proper sort constraint. Rare

INCOMPATIBILITY in situations where the previous misbehaviour has been

exploited.

* Refinement of user-space type system in type classes: pseudo-local

operations behave more similar to abbreviations. Potential

INCOMPATIBILITY in exotic situations.

*** HOL ***

* The 'typedef' command has been upgraded from a partially checked

"axiomatization", to a full definitional specification that takes the

global collection of overloaded constant / type definitions into

account. Type definitions with open dependencies on overloaded

definitions need to be specified as "typedef (overloaded)". This

provides extra robustness in theory construction. Rare INCOMPATIBILITY.

* Qualification of various formal entities in the libraries is done more

uniformly via "context begin qualified definition ... end" instead of

old-style "hide_const (open) ...". Consequently, both the defined

constant and its defining fact become qualified, e.g. Option.is_none and

Option.is_none_def. Occasional INCOMPATIBILITY in applications.

* Some old and rarely used ASCII replacement syntax has been removed.

INCOMPATIBILITY, standard syntax with symbols should be used instead.

The subsequent commands help to reproduce the old forms, e.g. to

simplify porting old theories:

  notation iff  (infixr "<->" 25)

  notation Times  (infixr "<*>" 80)

  type_notation Map.map  (infixr "~=>" 0)

  notation Map.map_comp  (infixl "o'_m" 55)

  type_notation FinFun.finfun ("(_ =>f /_)" [22, 21] 21)