languages/m4/doc/features.pod
State of implementation.

languages/m4/doc/freezing.pod
Saving and restoring the state of Parrot m4.

languages/m4/doc/operation.pod
How does this thing work?.

languages/m4/doc/running.pod
Using Parrot m4.

languages/m4/examples/eval.pir
Integer arithmetic evaluation for Parrot m4.

languages/m4/lib/Parrot/Test/M4.pm
Testing routines specific to 'm4'.

languages/m4/src/builtin.pir
builtin and user defined macros.

languages/m4/src/freeze.pir
reading and writing of state files.

languages/m4/src/input.pir
Setting up input and reading input.

languages/m4/src/m4.pir
An implementation of GNU m4 in Parrot Intermediate Representation.

languages/m4/src/macro.pir
does macro substitution.

languages/m4/src/output.pir
handle output for Parrot m4.

languages/m4/t/harness
A harness for Parrot m4.

languages/m4/t/regex/002_tokens.t
Test the PGE rules used by Parrot m4.

languages/m4/tools/scrutinize.pl
check Perl code with Perl::Critic.