mirror of
https://github.com/kanaka/mal.git
synced 2024-10-27 06:40:14 +03:00
159 lines
3.4 KiB
Perl
159 lines
3.4 KiB
Perl
#!/usr/bin/perl
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use strict;
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use warnings FATAL => 'recursion';
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use File::Basename 'dirname';
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use lib dirname(__FILE__);
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use English '-no_match_vars';
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use List::Util qw(pairs pairmap);
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use Readline qw(mal_readline set_rl_mode);
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use Types qw(nil false);
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use Reader qw(read_str);
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use Printer qw(pr_str);
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use Env;
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use Core qw(%NS);
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# False positives because of TCO.
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## no critic (Subroutines::RequireArgUnpacking)
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# read
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sub READ {
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my $str = shift;
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return read_str($str);
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}
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# eval
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my %special_forms = (
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'def!' => \&special_def,
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'let*' => \&special_let,
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'do' => \&special_do,
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'if' => \&special_if,
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'fn*' => \&special_fn,
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);
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sub EVAL {
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my ( $ast, $env ) = @_;
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my $dbgeval = $env->get('DEBUG-EVAL');
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if ( $dbgeval
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and not $dbgeval->isa('Mal::Nil')
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and not $dbgeval->isa('Mal::False') )
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{
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print 'EVAL: ', pr_str($ast), "\n" or die $ERRNO;
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}
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if ( $ast->isa('Mal::Symbol') ) {
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return $env->get( ${$ast} ) // die "'${$ast}' not found\n";
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}
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if ( $ast->isa('Mal::Vector') ) {
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return Mal::Vector->new( [ map { EVAL( $_, $env ) } @{$ast} ] );
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}
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if ( $ast->isa('Mal::HashMap') ) {
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return Mal::HashMap->new(
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{ pairmap { $a => EVAL( $b, $env ) } %{$ast} } );
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}
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if ( $ast->isa('Mal::List') and @{$ast} ) {
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my ( $a0, @args ) = @{$ast};
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if ( $a0->isa('Mal::Symbol') and my $sf = $special_forms{ ${$a0} } ) {
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@_ = ( $env, @args );
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goto &{$sf};
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}
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my $f = EVAL( $a0, $env );
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@_ = map { EVAL( $_, $env ) } @args;
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goto &{$f};
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}
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return $ast;
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}
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sub special_def {
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my ( $env, $sym, $val ) = @_;
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return $env->set( ${$sym}, EVAL( $val, $env ) );
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}
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sub special_let {
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my ( $env, $bindings, $body ) = @_;
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my $let_env = Env->new($env);
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foreach my $pair ( pairs @{$bindings} ) {
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my ( $k, $v ) = @{$pair};
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$let_env->set( ${$k}, EVAL( $v, $let_env ) );
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}
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@_ = ( $body, $let_env );
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goto &EVAL;
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}
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sub special_do {
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my ( $env, @todo ) = @_;
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my $final = pop @todo;
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for (@todo) {
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EVAL( $_, $env );
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}
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@_ = ( $final, $env );
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goto &EVAL;
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}
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sub special_if {
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my ( $env, $if, $then, $else ) = @_;
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my $cond = EVAL( $if, $env );
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if ( not $cond->isa('Mal::Nil') and not $cond->isa('Mal::False') ) {
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@_ = ( $then, $env );
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goto &EVAL;
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}
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if ($else) {
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@_ = ( $else, $env );
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goto &EVAL;
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}
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return nil;
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}
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sub special_fn {
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my ( $env, $params, $body ) = @_;
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return Mal::Function->new(
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sub {
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@_ = ( $body, Env->new( $env, $params, \@_ ) );
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goto &EVAL;
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}
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);
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}
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# print
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sub PRINT {
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my $exp = shift;
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return pr_str($exp);
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}
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# repl
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my $repl_env = Env->new();
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sub REP {
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my $str = shift;
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return PRINT( EVAL( READ($str), $repl_env ) );
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}
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# Command line arguments
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if ( $ARGV[0] eq '--raw' ) {
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set_rl_mode('raw');
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shift @ARGV;
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}
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# core.pl: defined using perl
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while ( my ( $k, $v ) = each %NS ) {
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$repl_env->set( $k, Mal::Function->new($v) );
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}
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# core.mal: defined using the language itself
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REP(q[(def! not (fn* (a) (if a false true)))]);
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while ( defined( my $line = mal_readline('user> ') ) ) {
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eval {
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print REP($line), "\n" or die $ERRNO;
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1;
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} or do {
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my $err = $EVAL_ERROR;
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print 'Error: ', $err or die $ERRNO;
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};
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}
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