.. | ||
tests | ||
Core.pm | ||
Dockerfile | ||
Env.pm | ||
Interop.pm | ||
Makefile | ||
Printer.pm | ||
Reader.pm | ||
Readline.pm | ||
README.md | ||
run | ||
step0_repl.pl | ||
step1_read_print.pl | ||
step2_eval.pl | ||
step3_env.pl | ||
step4_if_fn_do.pl | ||
step5_tco.pl | ||
step6_file.pl | ||
step7_quote.pl | ||
step8_macros.pl | ||
step9_try.pl | ||
stepA_mal.pl | ||
Types.pm |
Notes on the mal implementation in Perl5.
This implementation should work in any perl from 5.19.3 onwards.
Earlier versions are likely to work too as long as you install a new
List::Util. The implementation uses the experimental switch
feature, which may make it vulnerable to future changes in perl.
Mal objects are all in subclasses of Mal::Type
, and can be treated
as scalar, array, or hash references as appropriate.
Metadata support uses Hash::Util::FieldHash
to attach external
metadata to objects. This means that in the metadata system imposes
no overhead on the normal use of objects.
Hash-maps are slightly magical. They're keyed by the stringified
versions of mal objects, and Mal::Scalar
overloads stringification
so that this works properly.
Tail-call optimisation uses Perl's built-in goto &NAME
syntax for
explicit tail calls. This allows functions defined by fn*
to be
implemented as functions at the Perl layer.
Perl's garbage-collection is based on reference counting. This means
that reference loops will cause memory leaks, and in particular using
def!
to define a function will cause that function to have a
reference to the environment it's defined in, making a small reference
loop and hence a memory leak. This can be avoided by carefully
undefining any function before it goes out of scope.