reset_file_scope_vars
los tipos básicos INT, CHAR y VOID.
Este último se utilizará en las expresiones de tipo
para representar la ausencia de tipo.
pl@nereida:~/doc/casiano/PLBOOK/PLBOOK/code/Simple-Types/lib/Simple$ \
sed -ne '/^program:/,/^;/p' Types.eyp | cat -n
1 program:
2 {
3 reset_file_scope_vars();
4 }
5 definition<%name PROGRAM +>.program
6 {
7 $program->{symboltable} = { %st }; # creates a copy of the s.t.
8 $program->{depth} = 0;
9 $program->{line} = 1;
10 $program->{types} = { %type };
11 $program->{lines} = $tokenend;
12
13 my ($nondec, $declared) = $ids->end_scope($program->{symboltable}, $program, 'type');
14
15 if (@$nondec) {
16 warn "Identifier ".$_->key." not declared at line ".$_->line."\n" for @$nondec;
17 die "\n";
18 }
19
20 # Type checking: add a direct pointer to the data-structure
21 # describing the type
22 $_->{t} = $type{$_->{type}} for @$declared;
23
24 my $out_of_loops = $loops->end_scope($program);
25 if (@$out_of_loops) {
26 warn "Error: ".ref($_)." outside of loop at line $_->{line}\n" for @$out_of_loops;
27 die "\n";
28 }
29
30 # Check that are not dangling breaks
31 reset_file_scope_vars();
32
33 $program;
34 }
35 ;
Se procede a establecer el atributo t
como enlace directo a la expresión de tipo. Lo mismo se hace en las funciones
y en los bloques.
Sigue el código de reset_file_scope_vars:
pl@nereida:~/doc/casiano/PLBOOK/PLBOOK/code/Simple-Types/lib/Simple$ \
sed -ne '/^sub re.*vars/,/^}/p' Types.eyp | cat -n
1 sub reset_file_scope_vars {
2 %st = (); # reset symbol table
3 ($tokenbegin, $tokenend) = (1, 1);
4 %type = ( INT => Parse::Eyapp::Node->hnew('INT'),
5 CHAR => Parse::Eyapp::Node->hnew('CHAR'),
6 VOID => Parse::Eyapp::Node->hnew('VOID'),
7 );
8 $depth = 0;
9 $ids = Parse::Eyapp::Scope->new(
10 SCOPE_NAME => 'block',
11 ENTRY_NAME => 'info',
12 SCOPE_DEPTH => 'depth',
13 );
14 $loops = Parse::Eyapp::Scope->new(
15 SCOPE_NAME => 'exits',
16 );
17 $ids->begin_scope();
18 $loops->begin_scope(); # just for checking
19 }