lr/gen.c

#include"gen.h"

Gen gen_new(void)
{
	Gen gen={
		.labelno=0,
		.stackptr=NULL,
	};
	return gen;
}

void gen_free(Gen*gen)
{
	if(!gen)return;
}

void gen_setrootnode(Gen*gen,PNode*rootnode)
{
	if(!gen||!rootnode)return;
	gen->rootnode=rootnode;
}

// Convert infix to RPN
// Vec<Tok>
Vec gen_i2r(const Vec*tokens)
{
	Vec stack=vec_new(sizeof(const Tok));
	Vec operators=vec_new(sizeof(const Tok));
	int precedence[1024]={0};
	precedence['(']=5;
	precedence[')']=5;
	precedence['+']=10;
	precedence['-']=10;
	precedence['*']=20;
	precedence['/']=20;

	if(tokens->size>0)
	{
		for(size_t i=0;i<tokens->size;++i)
		{

			// identifiers
			switch(vec_at(tokens,i,const Tok*)->type)
			{

				// integers, keywords (true/false), identifiers
				case LIDENTIFIER:
				case LKEYWORD:
				case LINTEGER:
					vec_push(&stack,vec_at(tokens,i,const Tok*));
					break;

				// operators
				case LOPERATOR:
					{

						// '('
						if(vec_at(tokens,i,const Tok*)->subtype==LLPAREN)
						{
							vec_push(&operators,vec_at(tokens,i,const Tok*));
						}

						// ')'
						else if(vec_at(tokens,i,const Tok*)->subtype==LRPAREN)
						{
							while(operators.size>0&&vec_at(&operators,operators.size-1,const Tok*)->subtype!=LLPAREN)
							{
								const Tok*newtok=vec_at(&operators,operators.size-1,const Tok*);
								vec_push(&stack,newtok);
								vec_pop(&operators);
							}
							vec_pop(&operators);
						}

						// Default operators
						else
						{

							// Pop operators from operators ==> stack
							// who have higher precedence than current
							// operator
							while(operators.size>0&&precedence[(uint32_t)vec_at(&operators,operators.size-1,const Tok*)->str.buffer[0]]>=precedence[(uint32_t)vec_at(tokens,i,const Tok*)->str.buffer[0]])
							{
								const Tok*newtok=vec_at(&operators,operators.size-1,const Tok*);
								vec_push(&stack,newtok);
								vec_pop(&operators);
							}
							vec_push(&operators,vec_at(tokens,i,const Tok*));
						}

					}
			}

		}
	}

	while(operators.size>0)
	{
		const Tok*newtok=vec_at(&operators,operators.size-1,const Tok*);
		vec_push(&stack,newtok);
		vec_pop(&operators);
	}

	/* printf("s:"); */
	/* vec_print_tokens(&stack); */
	/* printf("o:"); */
	/* vec_print_tokens(&operators); */

	/* vec_free(&stack); */
	vec_free(&operators);

	// move ownership to caller
	return stack;
}