Gaëtan Gilbert edited this page Nov 10, 2018 · 10 revisions

The information below are valid for developing in Coq 8.10 (2018)

Developing Coq: A tutorial

Getting Coq sources

Coq sources are hosted on GitHub. The recommended way is to get them is:

git clone

Compiling Coq sources

Follow the instructions from the file INSTALL of the Coq archive

Basic developer setup

Development process might be faster by working locally and not installing Coq in the path. To do so run

./configure -local

The -local option means that you will not need to install coq to /usr/local but instead that you will run Coq directly from the bin subdirectory.

In fact, the recommended way of running configure for hacking Coq is ./configure -profile devel (which includes -local among other developer settings). An alternative way of building Coq is by using dune (run make -f Makefile.dune to learn about available targets).

Directory structure

The Coq archive contains the following subdirectories:

  • bin where binaries are created

  • dev miscellaneous information for developers

  • doc the Coq documentation and User's reference manual sources

  • man Coq man pages

  • tools sources of coqdoc, coqdep, coq-tex, coq_makefile, etc.

  • theories the Coq standard library

  • plugins sources of plugins (extraction, firstorder, ...)

  • test-suite the Coq test suite

The sources of Coq reside in the following directories

  • config OCaml files created by the configure script

  • lib utilities, general-purpose data structures, ...

  • kernel the Coq kernel, which implements the type-checker of the Calculus of Inductive Constructions

  • library global names, infrastructure for backtracking, reading/writing vo files, ...

  • pretyping unification, compilation of pattern-matching, type inference, coercions

  • engine low-level part of the proof engine

  • proofs high-level part of the proof engine

  • tactics specific tactics and the tactic language

  • interp syntax interpretation layer: notations, implicit arguments, globalization of names, ...

  • parsing parsers

  • printing printers

  • stm the state transition machine for asynchronous evaluation

  • vernac vernacular commands

  • toplevel interactive loop, treatment of options, ...

  • ide source of the CoqIDE graphical interface

.mlp files

The Coq source contains the usual OCaml .ml and .mli files but it also contains .mlg files that need to be preprocessed by coqpp, and .mlp files preprocessed by camlp5 (the later will probably be removed between 8.9 and 8.10, they're only used for processing the deprecated .ml4 files in external plugins).

Main developer targets

A complete compilation is done by make world. It takes about 10 minutes with option -j4 on a 4 core processor.

When developing, you may use partial targets such as:

  • states builds the initial state, this is required to run Coq.

  • byte builds bin/coqtop.byte and plugins in byte code; this is the fastest target when debugging the OCaml code.

  • bin/coqtop pluginsopt to compile Coq to native code.

  • coqide builds CoqIDE and the initial state but no standard library.

  • coqbinaries compiles bin/coqtop, bin/coqc, bin/coqchk but neither bin/coqide nor the library


The compiling process require preprocessing, which requires some compiling, this is why the following sequence should better be respected when adding new files to Coq:

  • make clean for binary compatibility
  • make world to rebuild (or simply make)

Another way to clean the archive from all non-registered files is to use git clean -fxd.

Adding a new file

Files to be linked are registered in files named directory/directory.mllib (e.g. pretyping/pretyping.mllib). The files must be given in an order compatible with the linking dependency order.

Simple debugging with Drop

Now run bin/coqtop.byte and type Drop.. This will drop to the OCaml toplevel. Then type:

#use "include";;
#trace String.uppercase;; (* or any name of a function you'd like to trace *)

The last go() restarts the Coq parser. You can type any Coq command and observe when it calls the function asked to be traced.

Debugging with ocamldebug

Look at file dev/doc/debugging.txt in the archive.

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