84 lines
1.9 KiB
C
84 lines
1.9 KiB
C
#include "parse.h"
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#include <assert.h>
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#include <string.h>
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void parse_init(am_t *am, parse_ctx_t *out)
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{
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out->am = am;
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out->state = PARSE_STATE_INIT;
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out->sp = out->stack + PARSE_MAX_DEPTH - 1;
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}
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static void push_state(parse_ctx_t *ctx, parse_state_t state)
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{
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assert(ctx->sp >= ctx->stack);
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*ctx->sp-- = state;
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}
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static parse_state_t pop_state(parse_ctx_t *ctx)
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{
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assert(ctx->sp < ctx->stack + PARSE_MAX_DEPTH - 1);
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return *++ctx->sp;
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}
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parse_state_t parse_proc(parse_ctx_t *ctx, const token_t *token)
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{
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switch (ctx->state) {
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case PARSE_STATE_INIT:
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switch (token->type) {
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case TOKEN_TYPE_INTEGER:
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AM_EXPR(ctx->am) = expr_integer(ctx->am, token->integer);
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ctx->state = PARSE_STATE_DONE;
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break;
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case TOKEN_TYPE_SYMBOL:
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AM_EXPR(ctx->am) = expr_symbol(ctx->am, &token->symbol);
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ctx->state = PARSE_STATE_DONE;
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break;
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case TOKEN_TYPE_OPEN_PAREN:
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push_state(ctx, PARSE_STATE_DONE);
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AM_EXPR(ctx->am) = expr_empty_list(ctx->am);
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ctx->state = PARSE_STATE_LIST;
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break;
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case TOKEN_TYPE_CLOSE_PAREN:
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ctx->state = PARSE_STATE_ERROR;
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break;
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}
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break;
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case PARSE_STATE_LIST:
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switch (token->type) {
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case TOKEN_TYPE_INTEGER:
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AM_VAL(ctx->am) = expr_integer(ctx->am, token->integer);
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am_append(ctx->am, EXPR, VAL);
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break;
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case TOKEN_TYPE_SYMBOL:
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AM_VAL(ctx->am) = expr_symbol(ctx->am, &token->symbol);
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am_append(ctx->am, EXPR, VAL);
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break;
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case TOKEN_TYPE_OPEN_PAREN:
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am_push(ctx->am, EXPR);
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push_state(ctx, PARSE_STATE_LIST);
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AM_EXPR(ctx->am) = expr_empty_list(ctx->am);
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ctx->state = PARSE_STATE_LIST;
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break;
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case TOKEN_TYPE_CLOSE_PAREN:
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ctx->state = pop_state(ctx);
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if (ctx->state == PARSE_STATE_LIST) {
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AM_VAL(ctx->am) = AM_EXPR(ctx->am);
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am_pop(ctx->am, EXPR);
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am_append(ctx->am, EXPR, VAL);
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}
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break;
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}
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break;
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case PARSE_STATE_DONE:
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case PARSE_STATE_ERROR:
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break;
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}
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assert(ctx->state != PARSE_STATE_INIT);
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return ctx->state;
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}
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