Compiler/lexical analyzer: Difference between revisions
→{{header|Perl 6}}: Modified to comply with task requirements
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=={{header|Perl 6}}==
This is more complicated than strictly necessary for this task. It is set up to be easily adapted to do syntax analysis.
(Note: there are several bogus comments added strictly to help with syntax highlighting.)
{{works with|Rakudo|2016.08}}
<lang perl6>grammar tiny_C {
rule TOP { ^ <.whitespace>? <tokens> + % <.whitespace> <.whitespace> <eoi> }
rule whitespace { [
token comment
token tokens {
[
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]
}
proto token
token operator:sym<*>
token operator:sym</>
token operator:sym<+>
token operator:sym<->
token operator:sym('<='){ '<='
token operator:sym('<') { '<' { make 'OP_LESS' } }
token operator:sym('>') { '>' { make 'OP_GREATER' } }
token operator:sym<!=> { '!=' { make 'OP_NOTEQUAL' } }
token operator:sym<=> { '=' { make 'OP_ASSIGN' } }
token operator:sym<&&> { '&&' { make 'OP_AND' } }
proto token keyword {*}
token keyword:sym<if> { 'if' { make 'KEYWORD_IF' } }
token keyword:sym<putc> { 'putc' { make 'KEYWORD_PUTC' } }
token keyword:sym<while> { 'while' { make 'KEYWORD_WHILE' } }
token keyword:sym<print> { 'print' { make 'KEYWORD_PRINT' } }
proto token symbol {*}
token symbol:sym<(> { '(' { make 'LEFT_PAREN' } }
token symbol:sym<)> { ')' { make 'RIGHT_PAREN' } }
token symbol:sym<{> { '{' { make 'LEFT_BRACE' } }
token symbol:sym<}> { '}' { make 'RIGHT_BRACE' } }
token symbol:sym<;> { ';' { make 'SEMICOLON' } }
token symbol:sym<,> { ',' { make 'COMMA' } }
token identifier { <[_A..Za..z]><[_A..Za..z0..9]>* { make 'IDENTIFER ' ~ $/ } }
token integer { <[0..9]>+ { make 'INTEGER ' ~ $/ } }
token char {
'\'' [<-[']> | '\n' | '\\\\'] '\''
{ make 'CHAR_LITERAL ' ~ $/.subst("\\n", "\n").substr(1, *-1).ord }
}
token string {
'"' <-["\n]>* '"' #'
{
make 'STRING ' ~ $/;
note 'Error: Unknown escape sequence.' and exit if (~$/ ~~ m:r/ <!after <[\\]>>[\\<-[n\\]>]<!before <[\\]>> /);
}
}
token eoi { $ { make 'END_OF_INPUT' } }
token error {
| '\'''\'' { note 'Error: Empty character constant.' and exit }
| '\'' <-[']> ** {2..*} '\'' { note 'Error: Multi-character constant.' and exit }
| '/*' <-[*]>* $ { note 'Error: End-of-file in comment.' and exit }
| '"' <-["]>* $ { note 'Error: End-of-file in string.' and exit }
| '"' <-["]>*? \n { note 'Error: End of line in string.' and exit } #'
}
}
sub parse_it ( $c_code ) {
my $l;
my @pos = gather for $c_code.lines».chars.kv -> $line, $v {
take [ $line + 1, $_ ] for 1 .. ($v+1); # v
$l = $line+2;
}
@pos.push: [ $l, 1 ]; # capture eoi
$/ =
or warn "Cannot parse";
for flat $/<
say join "\t", @pos[$m.from].fmt('%3d'), $m.ast; ;
}
}
my $tokenizer = tiny_C.parse(@*ARGS[0].IO.slurp);
parse_it( $tokenizer );</lang>
{{out}}
Using testcase 3
<pre> 5 15 KEYWORD_PRINT
5 41 OP_SUBTRACT
6 15 KEYWORD_PUTC
6 41 OP_LESS
7 15 KEYWORD_IF
7 41 OP_GREATER
8 15 KEYWORD_WHILE
8 41 OP_LESSEQUAL
9 15 LEFT_BRACE
9 41 OP_NOTEQUAL
10 15 RIGHT_BRACE
10 41 OP_AND
11 15 LEFT_PAREN
11 41 SEMICOLON
12 15 RIGHT_PAREN
12 41 COMMA
13 15 OP_SUBTRACT
13 41 OP_ASSIGN
14 15 OP_MULTIPLY
14 41 INTEGER 42
15 15 OP_DIVIDE
15 41 STRING "String literal"
16 15 OP_ADD
16 41 IDENTIFER variable_name
17 26 CHAR_LITERAL 10
18 26 CHAR_LITERAL 92
19 26 CHAR_LITERAL 32
20 1 END_OF_INPUT
</pre>
=={{header|Python}}==
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