madmaurice/Minilisp.pm
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Add debug mode for lexer

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madmaurice 2021-04-08 23:32:53 +02:00
parent cf9f90c19b
commit 4aaff13d91
1 changed files with 19 additions and 0 deletions
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19
lib/Minilisp.pm
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@ -34,26 +34,42 @@ sub tokenize {
$str =~ s/^\s+//;
$str =~ s/\s+$//;
my $debug = sub {};
$debug = sub {
my $msg = shift;
my $strcpy = $str;
$strcpy =~ s/^/ /mg;
print "-- $msg\n$strcpy\n";
} if !!$ENV{LEXER_DEBUG};
$debug->("Begin parsing");
while ($str)
{
if ($str =~ s/^;.*\n//)
{
$debug->("Comment");
# Comment. do nothing
}
elsif ($str =~ s/^\(//)
{
$debug->("Left parenthesis");
push @tokens, { type => LPAREN };
}
elsif($str =~ s/^\)//)
{
$debug->("Right parenthesis");
push @tokens, { type => RPAREN };
}
elsif($str =~ s/^'\(//) # short notation for lists
{
$debug->("Short list");
push @tokens, { type => LIST }, { type => LPAREN };
}
elsif($str =~ s/^'([^\s()"]+)//)
{
$debug->("Keyword $1");
push @tokens, {
type => KEYWORD,
value => $1,
@ -61,6 +77,7 @@ sub tokenize {
}
elsif($str =~ s/^"(([^"\\]|\\.)+)"//)
{
$debug->("String '$1'");
my $value = $1;
my %special_chars = (
@ -86,6 +103,7 @@ sub tokenize {
}
elsif($ident =~ /^-?([0-9]+|[0-9]*\.[0-9]*)$/)
{
$debug->("Number '$1'");
if($ident =~ s/^-//)
{
$ident = 0 - $ident;
@ -98,6 +116,7 @@ sub tokenize {
}
else
{
$debug->("Identifier '$1'");
push @tokens, {
type => IDENT,
value => $ident,