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%{
#include "node.h"
#include <cstdio>
#include <cstdlib>
NBlock *programBlock; /* the top level root node of our final AST */
extern int yylex();
void yyerror(const char *s) { std::printf("Error: %s\n", s);std::exit(1); }
%}
/* Represents the many different ways we can access our data */
%union {
Node *node;
NBlock *block;
NExpression *expr;
NStatement *stmt;
NIdentifier *ident;
NVariableDeclaration *var_decl;
std::vector<NVariableDeclaration*> *varvec;
std::vector<NExpression*> *exprvec;
std::string *string;
int token;
}
/* Define our terminal symbols (tokens). This should
match our tokens.l lex file. We also define the node type
they represent.
*/
%token <string> TIDENTIFIER TINTEGER TDOUBLE
%token <token> TCEQ TCNE TCLT TCLE TCGT TCGE TEQUAL
%token <token> TLPAREN TRPAREN TLBRACE TRBRACE TCOMMA TDOT
%token <token> TPLUS TMINUS TMUL TDIV
/* Define the type of node our nonterminal symbols represent.
The types refer to the %union declaration above. Ex: when
we call an ident (defined by union type ident) we are really
calling an (NIdentifier*). It makes the compiler happy.
*/
%type <ident> ident
%type <expr> numeric expr
%type <varvec> func_decl_args
%type <exprvec> call_args
%type <block> program stmts block
%type <stmt> stmt var_decl func_decl
%type <token> comparison
/* Operator precedence for mathematical operators */
%left TPLUS TMINUS
%left TMUL TDIV
%start program
%%
program : stmts { programBlock = $1; }
;
stmts : stmt { $$ = new NBlock(); $$->statements.push_back($<stmt>1); }
| stmts stmt { $1->statements.push_back($<stmt>2); }
;
stmt : var_decl | func_decl
| expr { $$ = new NExpressionStatement(*$1); }
;
block : TLBRACE stmts TRBRACE { $$ = $2; }
| TLBRACE TRBRACE { $$ = new NBlock(); }
;
var_decl : ident ident { $$ = new NVariableDeclaration(*$1, *$2); }
| ident ident TEQUAL expr { $$ = new NVariableDeclaration(*$1, *$2, $4); }
;
func_decl : ident ident TLPAREN func_decl_args TRPAREN block
{ $$ = new NFunctionDeclaration(*$1, *$2, *$4, *$6); delete $4; }
;
func_decl_args : /*blank*/ { $$ = new VariableList(); }
| var_decl { $$ = new VariableList(); $$->push_back($<var_decl>1); }
| func_decl_args TCOMMA var_decl { $1->push_back($<var_decl>3); }
;
ident : TIDENTIFIER { $$ = new NIdentifier(*$1); delete $1; }
;
numeric : TINTEGER { $$ = new NInteger(atol($1->c_str())); delete $1; }
| TDOUBLE { $$ = new NDouble(atof($1->c_str())); delete $1; }
;
expr : ident TEQUAL expr { $$ = new NAssignment(*$<ident>1, *$3); }
| ident TLPAREN call_args TRPAREN { $$ = new NMethodCall(*$1, *$3); delete $3; }
| ident { $<ident>$ = $1; }
| numeric
| expr comparison expr { $$ = new NBinaryOperator(*$1, $2, *$3); }
| TLPAREN expr TRPAREN { $$ = $2; }
;
call_args : /*blank*/ { $$ = new ExpressionList(); }
| expr { $$ = new ExpressionList(); $$->push_back($1); }
| call_args TCOMMA expr { $1->push_back($3); }
;
comparison : TCEQ | TCNE | TCLT | TCLE | TCGT | TCGE
| TPLUS | TMINUS | TMUL | TDIV
;
%%
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