Python-Frontend-Compiler/parser.y at master · SRavit1/Python-Frontend-Compiler · GitHub

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%{
void yyerror (char *s);
int yylex();

#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <stack>

#include "compile.h"
#include "nodescpp.h"
#include "llvm/ADT/StringRef.h"

int indent_level;

//Purpose: Keeping track of scope
//Purpose: Python allows redefinition of current_scope, LLVM doesn't
std::stack<std::map<llvm::StringRef, llvm::StringRef>*>* scope_stack = new std::stack<std::map<llvm::StringRef, llvm::StringRef>*>();
std::map<llvm::StringRef, llvm::StringRef>* current_scope = new std::map<llvm::StringRef, llvm::StringRef>();

std::vector<function_exp*>* program = new std::vector<function_exp*>();
std::vector<expression*>* main_block = new std::vector<expression*>();

%}

//Note: Pointer must be used in union because sizeof(obj) is unknown
%union {
	int int_val;
	float float_val;
	bool bool_val;

	char* string_val;
	class expression* exp;

	class body* body;

	class function_exp* fexp;
	std::vector<expression*>* expl;
	std::vector<std::string>* strl;
}

%start statement_list

%token DEF
%token RET

%token EQUAL

%token OPEN_PAREN
%token CLOSE_PAREN
%token COMMA
%token COLON
%token TAB

%token <string_val> IDENTIFIER
%token <int_val> INT_TOKEN
%token <float_val> FLOAT_TOKEN
%token <string_val> STRING_TOKEN
%token <int_val> BOOL_TOKEN
%token <string_val> OP

%type <exp> statement
%type <fexp> function_declaration

%type <exp> assignment
%type <exp> function_call
%type <exp> return

%type <expl> args_list
%type <strl> param_list
%type <body> body

%type <exp> expression
%type <exp> binary_expression
%type <exp> variable

//TODO: Precedence is not working
/*
%left '-' '+'
%left '*' '/'
*/
%%
statement_list: top_statement | statement_list top_statement;

top_statement:
	statement { main_block->push_back($1); }
	| function_declaration { program->push_back($1); }
	| "\n" top_statement {}
	;

statement:
	assignment { $$ = $1; }
	| function_call { $$ = $1; }
	| return { $$ = $1; }
	/*TODO: should not be called at top level*/
	/*TODO: Add while loop, control statement_list*/
	;

assignment:
	IDENTIFIER EQUAL expression {
		$$ = $3;


		typedef std::map<llvm::StringRef, llvm::StringRef>::const_iterator CI;
		bool identifier_present = 0;
		for (CI it = current_scope->begin(); it != current_scope->end(); ++it) {
			if (it->first == $1)
				identifier_present = 1;
		}

		if (!identifier_present) {
			(*current_scope)[$1] = $1;
			$$->setName($1);
		}
		else {
			int i = 1;
			std::string new_identifier;
			while(identifier_present) {
				new_identifier = $1 + i;
				identifier_present = 0;
				for (CI it = current_scope->begin(); it != current_scope->end(); ++it) {
					if (it->first == new_identifier)
						identifier_present = 1;
				}
				i++;
			}
			(*current_scope)[$1] = new_identifier;
			$$->setName(new_identifier);
		}
	}
	;

function_call:
	IDENTIFIER OPEN_PAREN args_list CLOSE_PAREN
		{
			function_call* fc = new function_call("fc_out", $1);
			for (auto arg: *$3) {
				std::cout<<"ARG TYPE: "<< arg->getType();
				std::cout<<" NAME: " << arg->getName();
				fc->addExpression(arg);
			}
			$$ = fc;
		}
	;
args_list:
	expression
		{
			$$ = new std::vector<expression*>();
			$$->push_back($1);
		}
	| args_list COMMA expression
		{
			$$=$1;
			$$->push_back($3);
		}
	;
return:
	RET expression
		{
			$$ = new return_statement("ret", $2);
		}
	;

function_declaration:
	DEF IDENTIFIER OPEN_PAREN CLOSE_PAREN COLON body
		{
			//TODO: Don't know ret type at this point
			std::vector<int> arg_types;
			std::vector<std::string> arg_names;

			$$ = new function_exp ($2, arg_types, arg_names, 0, $6->getBodyContent());
		}
	| DEF IDENTIFIER OPEN_PAREN param_list CLOSE_PAREN COLON body
		{
			//TODO: Don't know ret type at this point -- see above
			std::vector<int> arg_types($4->size());

			$$ = new function_exp ($2, arg_types, *$4, 0, $7->getBodyContent());
		}
	;

param_list:
	IDENTIFIER
		{
			$$ = new std::vector<std::string>();
			$$->push_back($1);

			//TEMPORARY FIX
			(*current_scope)[$1] = $1;
		}
	| param_list COMMA IDENTIFIER
		{
			$$ = $1;
			$$->push_back($3);

			//TEMPORARY FIX -- see above
			(*current_scope)[$3] = $3;
		}
	;

body:
	TAB statement
		{
			//TODO: Statement that comes here will be added to the previous scope
			std::vector<expression*>* body_content = new std::vector<expression*>();
			std::map<llvm::StringRef, llvm::StringRef>* scope = new std::map<llvm::StringRef, llvm::StringRef>();

			current_scope = scope;
			scope_stack->push(scope);

			$$ = new body(body_content, scope);
			$$->addExpression($2);
		}
	| body TAB statement
		{
			$$ = $1;
			$$->addExpression($3);
		}
	;

expression:
	OPEN_PAREN expression CLOSE_PAREN { $$ = $2; }
	| binary_expression { $$ = $1; }
	| variable { $$ = $1; }
	| function_call { $$ = $1; }
	| INT_TOKEN {
		$$ = new integer_const("", $1);
	}
	| FLOAT_TOKEN {
		$$ = new float_const("", $1);
	}
	| STRING_TOKEN {
		$$ = new string_const("", $1);
	}
	| BOOL_TOKEN {
		$$ = new bool_const("", $1);
	}
	;

binary_expression:
	expression OP expression
		{
			$$ = new binary_expression("", $2, $1, $3);
		}
	;

variable:
	IDENTIFIER
		{
			/*
			TODO: Variable may not be in current scope
			*/
			std::string var_name = (*current_scope)[$1];
			variable* var = new variable($1); //changed from var_name
			$$ = var;
		}
	;
%%

int main (void) {
	#ifndef YYDEBUG
	yydebug = 1;
	#endif

	int result = yyparse();

	//Add return to main_block if not present
	//Add return types for function args
	//Add return type for functions
	function_exp* main = new function_exp("main", {0}, {"var"}, 0, main_block);
	std::string in_name = "var";
	(*current_scope)[in_name] = in_name;
	program->push_back(main);

	compile(program);

	return result;
}

void yyerror (char *s) {fprintf (stderr, "%s\n", s);}