
# Commands¶

## Displaying¶

Command Print Term? reference univ_name_list?
::=@{ name* }

Displays definitions of terms, including opaque terms, for the object reference.

• Term - a syntactic marker to allow printing a term that is the same as one of the various Print commands. For example, Print All is a different command, while Print Term All shows information on the object whose name is "All".

• univ_name_list - locally renames the polymorphic universes of reference. The name _ means the usual name is printed.

Error qualid not a defined object.
Error Universe instance should have length natural.
Error This object does not support universe names.
Command Print All

This command displays information about the current state of the environment, including sections and modules.

Command Inspect natural

This command displays the natural last objects of the current environment, including sections and modules.

Command Print Section qualid

Displays the objects defined since the beginning of the section named qualid.

## Query commands¶

Unlike other commands, query_commands may be prefixed with a goal selector (natural:) to specify which goals it applies to. If no selector is provided, the command applies to the current goal. If no proof is open, then the command only applies to accessible objects. (see Section Invocation of tactics).

Eval and Compute are also query_commands, which are described elsewhere

Command About reference univ_name_list?

Displays information about the reference object, which, if a proof is open, may be a hypothesis of the selected goal, or an accessible theorem, axiom, etc.: its kind (module, constant, assumption, inductive, constructor, abbreviation, …), long name, type, implicit arguments and argument scopes (as set in the definition of reference or subsequently with the Arguments command). It does not print the body of definitions or proofs.

Command Check term

Displays the type of term. When called in proof mode, the term is checked in the local context of the selected goal.

Command Search search_query+ inside​outside qualid+?

This command can be used to filter the goal and the global context to retrieve objects whose name or type satisfies a number of conditions. Library files that were not loaded with Require are not considered. The Search Blacklist table can also be used to exclude some things from all calls to Search.

The output of the command is a list of qualified identifiers and their types. If the Search Output Name Only flag is on, the types are omitted.

::=search_item||[ +| ]

Multiple search_items can be combined into a complex search_query:

- search_query

Excludes the objects that would be filtered by search_query. See this example.

[ search_query+ | ... | search_query+ ]

This is a disjunction of conjunctions of queries. A simple conjunction can be expressed by having a single disjunctive branch. For a conjunction at top-level, the surrounding brackets are not required.

::=headhypconclheadhypheadconcl :? string ?|headhypconclheadhypheadconcl :? one_pattern|is : logical_kind

Searched objects can be filtered by patterns, by the constants they contain (identified by their name or a notation) and by their names. The location of the pattern or constant within a term

one_pattern

Search for objects whose type contains a subterm matching the pattern one_pattern. Holes of the pattern are indicated by _ or ?ident. If the same ?ident occurs more than once in the pattern, all occurrences in the subterm must be identical. See this example.

string % scope_key?
• If string is a substring of a valid identifier and no % scope_key is provided, search for objects whose name contains string. See this example.

• Otherwise, search for objects whose type contains the reference that this string, interpreted as a notation, is attached to (as described in reference). See this example.

Note

To refer to a string used in a notation that is a substring of a valid identifier, put it between single quotes or explicitly provide a scope. See this example.

hyp:

The provided pattern or reference is matched against any subterm of an hypothesis of the type of the objects. See this example.

headhyp:

The provided pattern or reference is matched against the subterms in head position (any partial applicative subterm) of the hypotheses of the type of the objects. See the previous example.

concl:

The provided pattern or reference is matched against any subterm of the conclusion of the type of the objects. See this example.

headconcl:

The provided pattern or reference is matched against the subterms in head position (any partial applicative subterm) of the conclusion of the type of the objects. See the previous example.

head:

This is simply the union between headconcl: and headhyp:.

is: logical_kind
::=|DefinitionExampleContextPrimitive|CoercionInstanceSchemeCanonicalSubClass|FieldMethod

Filters objects by the keyword that was used to define them (Theorem, Lemma, Axiom, Variable, Context, Primitive...) or its status (Coercion, Instance, Scheme, Canonical, SubClass, Field for record fields, Method for class fields). Note that Coercions, Canonical Structures, Instances and Schemes can be defined without using those keywords. See this example.

• inside qualid+ - limit the search to the specified modules

• outside qualid+ - exclude the specified modules from the search

Error Module/section qualid not found.

There is no constant in the environment named qualid, where qualid is in an inside or outside clause.

Example: Searching for a pattern

Require Import PeanoNat.

We can repeat meta-variables to narrow down the search. Here, we are looking for commutativity lemmas.

Search (_ ?n ?m = _ ?m ?n).
Nat.land_comm: forall a b : nat, Nat.land a b = Nat.land b a Nat.lor_comm: forall a b : nat, Nat.lor a b = Nat.lor b a Nat.lxor_comm: forall a b : nat, Nat.lxor a b = Nat.lxor b a Nat.lcm_comm: forall a b : nat, Nat.lcm a b = Nat.lcm b a Nat.min_comm: forall n m : nat, Nat.min n m = Nat.min m n Nat.gcd_comm: forall n m : nat, Nat.gcd n m = Nat.gcd m n Bool.xorb_comm: forall b b' : bool, xorb b b' = xorb b' b Nat.max_comm: forall n m : nat, Nat.max n m = Nat.max m n Nat.mul_comm: forall n m : nat, n * m = m * n Nat.add_comm: forall n m : nat, n + m = m + n Bool.orb_comm: forall b1 b2 : bool, (b1 || b2)%bool = (b2 || b1)%bool Bool.andb_comm: forall b1 b2 : bool, (b1 && b2)%bool = (b2 && b1)%bool Nat.eqb_sym: forall x y : nat, (x =? y) = (y =? x)

Example: Searching for part of an identifier

Search "_assoc".
or_assoc: forall A B C : Prop, (A \/ B) \/ C <-> A \/ B \/ C and_assoc: forall A B C : Prop, (A /\ B) /\ C <-> A /\ B /\ C eq_trans_assoc: forall [A : Type] [x y z t : A] (e : x = y) (e' : y = z) (e'' : z = t), eq_trans e (eq_trans e' e'') = eq_trans (eq_trans e e') e''

Example: Searching for a reference by notation

Search "+".
plus_O_n: forall n : nat, 0 + n = n plus_n_O: forall n : nat, n = n + 0 plus_n_Sm: forall n m : nat, S (n + m) = n + S m plus_Sn_m: forall n m : nat, S n + m = S (n + m) mult_n_Sm: forall n m : nat, n * m + n = n * S m f_equal2_plus: forall x1 y1 x2 y2 : nat, x1 = y1 -> x2 = y2 -> x1 + x2 = y1 + y2 nat_rect_plus: forall (n m : nat) {A : Type} (f : A -> A) (x : A), nat_rect (fun _ : nat => A) x (fun _ : nat => f) (n + m) = nat_rect (fun _ : nat => A) (nat_rect (fun _ : nat => A) x (fun _ : nat => f) m) (fun _ : nat => f) n

Example: Disambiguating between part of identifier and notation

Require Import PeanoNat.

In this example, we show two ways of searching for all the objects whose type contains Nat.modulo but which do not contain the substring "mod".

Search "'mod'" -"mod".
Nat.bit0_eqb: forall a : nat, Nat.testbit a 0 = (a mod 2 =? 1) Nat.land_ones: forall a n : nat, Nat.land a (Nat.ones n) = a mod 2 ^ n Nat.div_exact: forall a b : nat, b <> 0 -> a = b * (a / b) <-> a mod b = 0 Nat.testbit_spec': forall a n : nat, Nat.b2n (Nat.testbit a n) = (a / 2 ^ n) mod 2 Nat.pow_div_l: forall a b c : nat, b <> 0 -> a mod b = 0 -> (a / b) ^ c = a ^ c / b ^ c Nat.testbit_eqb: forall a n : nat, Nat.testbit a n = ((a / 2 ^ n) mod 2 =? 1) Nat.testbit_false: forall a n : nat, Nat.testbit a n = false <-> (a / 2 ^ n) mod 2 = 0 Nat.testbit_true: forall a n : nat, Nat.testbit a n = true <-> (a / 2 ^ n) mod 2 = 1
Search "mod"%nat -"mod".
Nat.bit0_eqb: forall a : nat, Nat.testbit a 0 = (a mod 2 =? 1) Nat.land_ones: forall a n : nat, Nat.land a (Nat.ones n) = a mod 2 ^ n Nat.div_exact: forall a b : nat, b <> 0 -> a = b * (a / b) <-> a mod b = 0 Nat.testbit_spec': forall a n : nat, Nat.b2n (Nat.testbit a n) = (a / 2 ^ n) mod 2 Nat.pow_div_l: forall a b c : nat, b <> 0 -> a mod b = 0 -> (a / b) ^ c = a ^ c / b ^ c Nat.testbit_eqb: forall a n : nat, Nat.testbit a n = ((a / 2 ^ n) mod 2 =? 1) Nat.testbit_false: forall a n : nat, Nat.testbit a n = false <-> (a / 2 ^ n) mod 2 = 0 Nat.testbit_true: forall a n : nat, Nat.testbit a n = true <-> (a / 2 ^ n) mod 2 = 1

Example: Search in hypotheses

The following search shows the objects whose type contains bool in an hypothesis as a strict subterm only:

Add Search Blacklist "internal_".
Nat.bitwise: (bool -> bool -> bool) -> nat -> nat -> nat -> nat Byte.of_bits: bool * (bool * (bool * (bool * (bool * (bool * (bool * bool)))))) -> Byte.byte Byte.to_bits_of_bits: forall b : bool * (bool * (bool * (bool * (bool * (bool * (bool * bool)))))), Byte.to_bits (Byte.of_bits b) = b

Example: Search in conclusion

The following search shows the objects whose type contains bool in the conclusion as a strict subterm only:

Byte.to_bits: Byte.byte -> bool * (bool * (bool * (bool * (bool * (bool * (bool * bool)))))) andb_prop: forall a b : bool, (a && b)%bool = true -> a = true /\ b = true andb_true_intro: forall [b1 b2 : bool], b1 = true /\ b2 = true -> (b1 && b2)%bool = true Byte.to_bits_of_bits: forall b : bool * (bool * (bool * (bool * (bool * (bool * (bool * bool)))))), Byte.to_bits (Byte.of_bits b) = b bool_choice: forall [S : Set] [R1 R2 : S -> Prop], (forall x : S, {R1 x} + {R2 x}) -> {f : S -> bool | forall x : S, f x = true /\ R1 x \/ f x = false /\ R2 x}

Example: Search by keyword or status

The following search shows the definitions whose type is a nat or a function which returns a nat and the lemmas about +:

Search [ is:Definition headconcl:nat | is:Lemma (_ + _) ].
Nat.two: nat Nat.zero: nat Nat.one: nat Nat.succ: nat -> nat Nat.log2: nat -> nat Nat.sqrt: nat -> nat Nat.square: nat -> nat Nat.double: nat -> nat Nat.pred: nat -> nat Nat.ldiff: nat -> nat -> nat Nat.tail_mul: nat -> nat -> nat Nat.land: nat -> nat -> nat Nat.div: nat -> nat -> nat Nat.modulo: nat -> nat -> nat Nat.lor: nat -> nat -> nat Nat.lxor: nat -> nat -> nat Nat.of_hex_uint: Hexadecimal.uint -> nat Nat.of_uint: Decimal.uint -> nat Nat.of_num_uint: Number.uint -> nat length: forall [A : Type], list A -> nat plus_n_O: forall n : nat, n = n + 0 plus_O_n: forall n : nat, 0 + n = n plus_n_Sm: forall n m : nat, S (n + m) = n + S m plus_Sn_m: forall n m : nat, S n + m = S (n + m) mult_n_Sm: forall n m : nat, n * m + n = n * S m

The following search shows the instances whose type includes the classes Reflexive or Symmetric:

Require Import Morphisms.
Search is:Instance [ Reflexive | Symmetric ].
iff_Symmetric: Symmetric iff iff_Reflexive: Reflexive iff impl_Reflexive: Reflexive Basics.impl eq_Symmetric: forall {A : Type}, Symmetric eq eq_Reflexive: forall {A : Type}, Reflexive eq Equivalence_Symmetric: forall {A : Type} {R : Relation_Definitions.relation A}, Equivalence R -> Symmetric R Equivalence_Reflexive: forall {A : Type} {R : Relation_Definitions.relation A}, Equivalence R -> Reflexive R PER_Symmetric: forall {A : Type} {R : Relation_Definitions.relation A}, PER R -> Symmetric R PreOrder_Reflexive: forall {A : Type} {R : Relation_Definitions.relation A}, PreOrder R -> Reflexive R reflexive_eq_dom_reflexive: forall {A B : Type} {R' : Relation_Definitions.relation B}, Reflexive R' -> Reflexive (eq ==> R')%signature
Command SearchPattern one_pattern inside​outside qualid+?

Displays the name and type of all hypotheses of the selected goal (if any) and theorems of the current context ending with forall binder*,? Pi ->* C that match the pattern one_pattern.

See Search for an explanation of the inside/outside clauses.

Example: SearchPattern examples

Require Import Arith.
SearchPattern (_ + _ = _ + _).
Nat.add_comm: forall n m : nat, n + m = m + n plus_Snm_nSm: forall n m : nat, S n + m = n + S m Nat.add_succ_comm: forall n m : nat, S n + m = n + S m Nat.add_shuffle3: forall n m p : nat, n + (m + p) = m + (n + p) plus_assoc_reverse: forall n m p : nat, n + m + p = n + (m + p) Nat.add_assoc: forall n m p : nat, n + (m + p) = n + m + p Nat.add_shuffle0: forall n m p : nat, n + m + p = n + p + m f_equal2_plus: forall x1 y1 x2 y2 : nat, x1 = y1 -> x2 = y2 -> x1 + x2 = y1 + y2 Nat.add_shuffle2: forall n m p q : nat, n + m + (p + q) = n + q + (m + p) Nat.add_shuffle1: forall n m p q : nat, n + m + (p + q) = n + p + (m + q)
SearchPattern (nat -> bool).
Nat.odd: nat -> bool Init.Nat.odd: nat -> bool Nat.even: nat -> bool Init.Nat.even: nat -> bool Init.Nat.testbit: nat -> nat -> bool Nat.leb: nat -> nat -> bool Nat.eqb: nat -> nat -> bool Init.Nat.eqb: nat -> nat -> bool Nat.ltb: nat -> nat -> bool Nat.testbit: nat -> nat -> bool Init.Nat.leb: nat -> nat -> bool Init.Nat.ltb: nat -> nat -> bool BinNat.N.testbit_nat: BinNums.N -> nat -> bool BinPosDef.Pos.testbit_nat: BinNums.positive -> nat -> bool BinPos.Pos.testbit_nat: BinNums.positive -> nat -> bool BinNatDef.N.testbit_nat: BinNums.N -> nat -> bool
SearchPattern (forall l : list _, _ l l).
List.incl_refl: forall [A : Type] (l : list A), List.incl l l List.lel_refl: forall [A : Type] (l : list A), List.lel l l
SearchPattern (?X1 + _ = _ + ?X1).
Nat.add_comm: forall n m : nat, n + m = m + n
Command SearchRewrite one_pattern inside​outside qualid+?

Displays the name and type of all hypotheses of the selected goal (if any) and theorems of the current context that have the form forall binder*,? Pi ->* LHS = RHS where one_pattern matches either LHS or RHS.

See Search for an explanation of the inside/outside clauses.

Example: SearchRewrite examples

Require Import Arith.
SearchRewrite (_ + _ + _).
Nat.add_shuffle0: forall n m p : nat, n + m + p = n + p + m plus_assoc_reverse: forall n m p : nat, n + m + p = n + (m + p) Nat.add_assoc: forall n m p : nat, n + (m + p) = n + m + p Nat.add_shuffle1: forall n m p q : nat, n + m + (p + q) = n + p + (m + q) Nat.add_shuffle2: forall n m p q : nat, n + m + (p + q) = n + q + (m + p) Nat.add_carry_div2: forall (a b : nat) (c0 : bool), (a + b + Nat.b2n c0) / 2 = a / 2 + b / 2 + Nat.b2n (Nat.testbit a 0 && Nat.testbit b 0 || c0 && (Nat.testbit a 0 || Nat.testbit b 0))
Table Search Blacklist string

This table specifies a set of strings used to exclude lemmas from the results of Search, SearchPattern and SearchRewrite queries. A lemma whose fully-qualified name contains any of the strings will be excluded from the search results. The default blacklisted substrings are _subterm, _subproof and Private_.

Use the Add and Remove commands to update the set of blacklisted strings.

Flag Search Output Name Only

This flag restricts the output of search commands to identifier names; turning it on causes invocations of Search, SearchPattern, SearchRewrite etc. to omit types from their output, printing only identifiers.

## Requests to the environment¶

Command Print Assumptions reference

Displays all the assumptions (axioms, parameters and variables) a theorem or definition depends on.

The message "Closed under the global context" indicates that the theorem or definition has no dependencies.

Command Print Opaque Dependencies reference

Displays the assumptions and opaque constants that reference depends on.

Command Print Transparent Dependencies reference

Displays the assumptions and transparent constants that reference depends on.

Command Print All Dependencies reference

Displays all the assumptions and constants reference depends on.

Command Locate reference
::=qualid|

Displays the full name of objects from Coq's various qualified namespaces such as terms, modules and Ltac, thereby showing the module they are defined in. It also displays notation definitions.

qualid

refers to object names that end with qualid.

string % scope_key?

refers to definitions of notations. string can be a single token in the notation such as "->" or a pattern that matches the notation. See Locating notations.

% scope_key, if present, limits the reference to the scope bound to the delimiting key scope_key, such as, for example, %nat. (see Section Local interpretation rules for notations)

Command Locate Term reference

Like Locate, but limits the search to terms

Command Locate Module qualid

Like Locate, but limits the search to modules

Command Locate Ltac qualid

Like Locate, but limits the search to tactics

Command Locate Library qualid

Displays the full name, status and file system path of the module qualid, whether loaded or not.

Command Locate File string

Displays the file system path of the file ending with string. Typically, string has a suffix such as .cmo or .vo or .v file, such as Nat.v.

Example: Locate examples

Locate nat.
Inductive Coq.Init.Datatypes.nat
Locate Datatypes.O.
Constructor Coq.Init.Datatypes.O (shorter name to refer to it in current context is O)
Locate Init.Datatypes.O.
Constructor Coq.Init.Datatypes.O (shorter name to refer to it in current context is O)
Locate Coq.Init.Datatypes.O.
Constructor Coq.Init.Datatypes.O (shorter name to refer to it in current context is O)
Locate I.Dont.Exist.
No object of suffix I.Dont.Exist

## Printing flags¶

Flag Fast Name Printing

When this flag is turned on, Coq uses an asymptotically faster algorithm for the generation of unambiguous names of bound variables while printing terms. While faster, it is also less clever and results in a typically less elegant display, e.g. it will generate more names rather than reusing certain names across subterms. This flag is not enabled by default, because as Ltac observes bound names, turning it on can break existing proof scripts.

Coq offers the possibility of loading different parts of a whole development stored in separate files. Their contents will be loaded as if they were entered from the keyboard. This means that the loaded files are text files containing sequences of commands for Coq’s toplevel. This kind of file is called a script for Coq. The standard (and default) extension of Coq’s script files is .v.

Command Load Verbose? string​ident

Loads a file. If ident is specified, the command loads a file named ident.v, searching successively in each of the directories specified in the loadpath. (see Section Libraries and filesystem)

If string is specified, it must specify a complete filename. ~ and .. abbreviations are allowed as well as shell variables. If no extension is specified, Coq will use the default extension .v.

Files loaded this way can't leave proofs open, nor can Load be used inside a proof.

We discourage the use of Load; use Require instead. Require loads .vo files that were previously compiled from .v files.

Verbose displays the Coq output for each command and tactic in the loaded file, as if the commands and tactics were entered interactively.

Error Can’t find file ident on loadpath.
Error Load is not supported inside proofs.
Error Files processed by Load cannot leave open proofs.

## Compiled files¶

This section describes the commands used to load compiled files (see Chapter The Coq commands for documentation on how to compile a file). A compiled file is a particular case of a module called a library file.

Command Require Import​Export? qualid+

Loads compiled modules into the Coq environment. For each qualid, which has the form identprefix .* ident, the command searches for the logical name represented by the identprefixs and loads the compiled file ident.vo from the associated filesystem directory.

The process is applied recursively to all the loaded files; if they contain Require commands, those commands are executed as well. The compiled files must have been compiled with the same version of Coq. The compiled files are neither replayed nor rechecked.

• Import - additionally does an Import on the loaded module, making components defined in the module available by their short names

• Export - additionally does an Export on the loaded module, making components defined in the module available by their short names and marking them to be exported by the current module

If the required module has already been loaded, Import and Export make the command equivalent to Import or Export.

The loadpath must contain the same mapping used to compile the file (see Section Libraries and filesystem). If several files match, one of them is picked in an unspecified fashion. Therefore, library authors should use a unique name for each module and users are encouraged to use fully-qualified names or the From … Require command to load files.

Command From dirpath Require Import​Export? qualid+

Works like Require, but loads, for each qualid, the library whose fully-qualified name matches dirpath.ident .*qualid for some ident .*. This is useful to ensure that the qualid library comes from a particular package.

Error Cannot load qualid: no physical path bound to dirpath.
Error Cannot find library foo in loadpath.

The command did not find the file foo.vo. Either foo.v exists but is not compiled or foo.vo is in a directory which is not in your LoadPath (see Section Libraries and filesystem).

Error Compiled library ident.vo makes inconsistent assumptions over library qualid.

The command tried to load library file ident.vo that depends on some specific version of library qualid which is not the one already loaded in the current Coq session. Probably ident.v was not properly recompiled with the last version of the file containing module qualid.

Error Bad magic number.

The file ident.vo was found but either it is not a Coq compiled module, or it was compiled with an incompatible version of Coq.

Error The file ident.vo contains library qualid1 and not library qualid2.

The library qualid2 is indirectly required by a Require or From … Require command. The loadpath maps qualid2 to ident.vo, which was compiled using a loadpath that bound it to qualid1. Usually the appropriate solution is to recompile ident.v using the correct loadpath. See Libraries and filesystem.

Warning Require inside a module is deprecated and strongly discouraged. You can Require a module at toplevel and optionally Import it inside another one.

Note that the Import and Export commands can be used inside modules.

Chapter The Coq commands

Command Print Libraries

This command displays the list of library files loaded in the current Coq session.

Command Declare ML Module string+

This commands dynamically loads OCaml compiled code from a .mllib file. It is used to load plugins dynamically. The files must be accessible in the current OCaml loadpath (see command line option -I and command Add ML Path). The .mllib suffix may be omitted.

This command is reserved for plugin developers, who should provide a .v file containing the command. Users of the plugins will then generally load the .v file.

This command supports the local attribute. If present, the listed files are not exported, even if they're outside a section.

Error File not found on loadpath: string.
Command Print ML Modules

This prints the name of all OCaml modules loaded with Declare ML Module. To know from where these module were loaded, the user should use the command Locate File.

Loadpaths are preferably managed using Coq command line options (see Section Libraries and filesystem), but there are also commands to manage them within Coq. These commands are only meant to be issued in the toplevel, and using them in source files is discouraged.

Command Pwd

This command displays the current working directory.

Command Cd string?

If string is specified, changes the current directory according to string which can be any valid path. Otherwise, it displays the current directory.

Command Add LoadPath string as dirpath
::=* ident

This command is equivalent to the command line option -Q string dirpath. It adds a mapping to the loadpath from the logical name dirpath to the file system directory string.

• dirpath is a prefix of a module name. The module name hierarchy follows the file system hierarchy. On Linux, for example, the prefix A.B.C maps to the directory string/B/C. Avoid using spaces after a . in the path because the parser will interpret that as the end of a command or tactic.

Command Add Rec LoadPath string as dirpath

This command is equivalent to the command line option -R string dirpath. It adds the physical directory string and all its subdirectories to the current Coq loadpath.

Command Remove LoadPath string

This command removes the path string from the current Coq loadpath.

Command Print LoadPath dirpath?

This command displays the current Coq loadpath. If dirpath is specified, displays only the paths that extend that prefix.

Command Add ML Path string

Equivalent to the command line option -I string. Adds the path string to the current OCaml loadpath (cf. Declare ML Module). It is for convenience, such as for use in an interactive session, and it is not exported to compiled files. For separation of concerns with respect to the relocability of files, we recommend using -I string.

Command Print ML Path

Displays the current OCaml loadpath, as provided by the command line option -I string or by the command Add ML Path @string (cf. Declare ML Module).

## Backtracking¶

The backtracking commands described in this section can only be used interactively, they cannot be part of a Coq file loaded via Load or compiled by coqc.

Command Reset ident

This command removes all the objects in the environment since ident was introduced, including ident. ident may be the name of a defined or declared object as well as the name of a section. One cannot reset over the name of a module or of an object inside a module.

Error ident: no such entry.
Command Reset Initial

Goes back to the initial state, just after the start of the interactive session.

Command Back natural?

Undoes all the effects of the last natural sentences. If natural is not specified, the command undoes one sentence. Sentences read from a .v file via a Load are considered a single sentence. While Back can undo tactics and commands executed within proof mode, once you exit proof mode, such as with Qed, all the statements executed within are thereafter considered a single sentence. Back immediately following Qed gets you back to the state just after the statement of the proof.

Error Invalid backtrack.

The user wants to undo more commands than available in the history.

Command BackTo natural

This command brings back the system to the state labeled natural, forgetting the effect of all commands executed after this state. The state label is an integer which grows after each successful command. It is displayed in the prompt when in -emacs mode. Just as Back (see above), the BackTo command now handles proof states. For that, it may have to undo some extra commands and end on a state natural′ ≤ natural if necessary.

## Quitting and debugging¶

Command Quit

Causes Coq to exit. Valid only in coqtop.

Command Drop

This command temporarily enters the OCaml toplevel. It is a debug facility used by Coq’s implementers. Valid only in the bytecode version of coqtop. The OCaml command:

#use "include";;


adds the right loadpaths and loads some toplevel printers for all abstract types of Coq- section_path, identifiers, terms, judgments, …. You can also use the file base_include instead, that loads only the pretty-printers for section_paths and identifiers. You can return back to Coq with the command:

go();;


Warning

1. It only works with the bytecode version of Coq (i.e. coqtop.byte, see Section interactive-use).

2. You must have compiled Coq from the source package and set the environment variable COQTOP to the root of your copy of the sources (see Section customization-by-environment-variables).

Command Time sentence

Executes sentence and displays the time needed to execute it.

Command Redirect string sentence

Executes sentence, redirecting its output to the file "string.out".

Command Timeout natural sentence

Executes sentence. If the operation has not terminated after natural seconds, then it is interrupted and an error message is displayed.

Option Default Timeout natural

When this option is set, each sentence is treated as if it was prefixed with Timeout natural, except for Timeout commands themselves. If unset, no timeout is applied.

Command Fail sentence

For debugging scripts, sometimes it is desirable to know whether a command or a tactic fails. If sentence fails, then Fail sentence succeeds (except for critical errors, such as "stack overflow"), without changing the proof state. In interactive mode, the system prints a message confirming the failure.

Error The command has not failed!

If the given command succeeds, then Fail sentence fails with this error message.

Note

Time, Redirect, Timeout and Fail are control_commands. For these commands, attributes and goal selectors, when specified, are part of the sentence argument, and thus come after the control command prefix and before the inner command or tactic. For example: Time #[ local ] Definition foo := 0. or Fail Timeout 10 all: auto.

## Controlling display¶

Flag Silent

This flag controls the normal displaying.

Option Warnings "-​+? ident+,"

This option configures the display of warnings. It is experimental, and expects, between quotes, a comma-separated list of warning names or categories. Adding - in front of a warning or category disables it, adding + makes it an error. It is possible to use the special categories all and default, the latter containing the warnings enabled by default. The flags are interpreted from left to right, so in case of an overlap, the flags on the right have higher priority, meaning that A,-A is equivalent to -A.

Option Debug "-? ident+,"

This option configures the display of debug messages. Each ident enables debug messages for that component, while -ident disables messages for the component. all activates or deactivates all other components. backtrace controls printing of error backtraces.

Test Debug displays the list of components and their enabled/disabled state.

Option Printing Width natural

This option sets which left-aligned part of the width of the screen is used for display. At the time of writing this documentation, the default value is 78.

Option Printing Depth natural

This option controls the nesting depth of the formatter used for pretty- printing. Beyond this depth, display of subterms is replaced by dots. At the time of writing this documentation, the default value is 50.

Flag Printing Compact Contexts

This flag controls the compact display mode for goals contexts. When on, the printer tries to reduce the vertical size of goals contexts by putting several variables (even if of different types) on the same line provided it does not exceed the printing width (see Printing Width). At the time of writing this documentation, it is off by default.

Flag Printing Unfocused

This flag controls whether unfocused goals are displayed. Such goals are created by focusing other goals with bullets (see Bullets or curly braces). It is off by default.

Flag Printing Dependent Evars Line

This flag controls the printing of the “(dependent evars: …)” information after each tactic. The information is used by the Prooftree tool in Proof General. (https://askra.de/software/prooftree)

## Printing constructions in full¶

Flag Printing All

Coercions, implicit arguments, the type of pattern matching, but also notations (see Syntax extensions and notation scopes) can obfuscate the behavior of some tactics (typically the tactics applying to occurrences of subterms are sensitive to the implicit arguments). Turning this flag on deactivates all high-level printing features such as coercions, implicit arguments, returned type of pattern matching, notations and various syntactic sugar for pattern matching or record projections. Otherwise said, Printing All includes the effects of the flags Printing Implicit, Printing Coercions, Printing Synth, Printing Projections, and Printing Notations. To reactivate the high-level printing features, use the command Unset Printing All.

Note

In some cases, setting Printing All may display terms that are so big they become very hard to read. One technique to work around this is use Undelimit Scope and/or Close Scope to turn off the printing of notations bound to particular scope(s). This can be useful when notations in a given scope are getting in the way of understanding a goal, but turning off all notations with Printing All would make the goal unreadable.

## Controlling Typing Flags¶

Flag Guard Checking

This flag can be used to enable/disable the guard checking of fixpoints. Warning: this can break the consistency of the system, use at your own risk. Decreasing argument can still be specified: the decrease is not checked anymore but it still affects the reduction of the term. Unchecked fixpoints are printed by Print Assumptions.

Attribute bypass_check(guard= yes​no?)

This boolean attribute is similar to the Guard Checking flag, but on a per-declaration basis. Disable guard checking locally with bypass_check(guard).

Flag Positivity Checking

This flag can be used to enable/disable the positivity checking of inductive types and the productivity checking of co-inductive types. Warning: this can break the consistency of the system, use at your own risk. Unchecked (co)inductive types are printed by Print Assumptions.

Attribute bypass_check(positivity= yes​no?)

This boolean attribute is similar to the Positivity Checking flag, but on a per-declaration basis. Disable positivity checking locally with bypass_check(positivity).

Flag Universe Checking

This flag can be used to enable/disable the checking of universes, providing a form of "type in type". Warning: this breaks the consistency of the system, use at your own risk. Constants relying on "type in type" are printed by Print Assumptions. It has the same effect as -type-in-type command line argument (see By command line options).

Attribute bypass_check(universes= yes​no?)

This boolean attribute is similar to the Universe Checking flag, but on a per-declaration basis. Disable universe checking locally with bypass_check(universes).

Command Print Typing Flags

Print the status of the three typing flags: guard checking, positivity checking and universe checking.

See also Cumulative StrictProp in the $$\SProp$$ chapter.

Example

Unset Guard Checking.
Print Typing Flags.
check_guarded: false check_positive: true check_universes: true cumulative sprop: false definitional uip: false
Fixpoint f (n : nat) : False   := f n.
f is defined f is recursively defined (guarded on 1st argument)
Fixpoint ackermann (m n : nat) {struct m} : nat :=   match m with   | 0 => S n   | S m =>     match n with     | 0 => ackermann m 1     | S n => ackermann m (ackermann (S m) n)     end   end.
ackermann is defined ackermann is recursively defined (guarded on 1st argument)
Print Assumptions ackermann.
Axioms: ackermann is assumed to be guarded.

Note that the proper way to define the Ackermann function is to use an inner fixpoint:

Fixpoint ack m :=   fix ackm n :=   match m with   | 0 => S n   | S m' =>     match n with     | 0 => ack m' 1     | S n' => ack m' (ackm n')     end   end.
ack is defined ack is recursively defined (guarded on 1st argument)

Typing flags may not be changed while inside sections.

## Internal registration commands¶

Due to their internal nature, the commands that are presented in this section are not for general use. They are meant to appear only in standard libraries and in support libraries of plug-ins.

### Exposing constants to OCaml libraries¶

Command Register qualid1 as qualid2

Makes the constant qualid1 accessible to OCaml libraries under the name qualid2. The constant can then be dynamically located in OCaml code by calling Coqlib.lib_ref "qualid2". The OCaml code doesn't need to know where the constant is defined (what file, module, library, etc.).

As a special case, when the first segment of qualid2 is kernel, the constant is exposed to the kernel. For instance, the PrimInt63 module features the following declaration:

Register bool as kernel.ind_bool.

This makes the kernel aware of the bool type, which is used, for example, to define the return type of the #int63_eq primitive.

### Inlining hints for the fast reduction machines¶

Command Register Inline qualid

Gives a hint to the reduction machines (VM and native) that the body of the constant qualid should be inlined in the generated code.

### Registering primitive operations¶

Command Primitive ident_decl : term? := #ident

Makes the primitive type or primitive operator #ident defined in OCaml accessible in Coq commands and tactics. For internal use by implementors of Coq's standard library or standard library replacements. No space is allowed after the #. Invalid values give a syntax error.

For example, the standard library files PrimInt63.v and PrimFloat.v use Primitive to support, respectively, the features described in Primitive Integers and Primitive Floats.

The types associated with an operator must be declared to the kernel before declaring operations that use the type. Do this with Primitive for primitive types and Register with the kernel prefix for other types. For example, in PrimInt63.v, #int63_type must be declared before the associated operations.

Error The type ident must be registered before this construction can be typechecked.

The type must be defined with Primitive command before this Primitive command (declaring an operation using the type) will succeed.