76 lines
1.7 KiB
C
76 lines
1.7 KiB
C
#include "ctx.h"
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#include <ivy/lang/ast.h>
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bool parse_match(struct ivy_parser *parser, struct ivy_ast_node **out)
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{
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if (!parse_keyword(parser, IVY_KW_MATCH)) {
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parse_trace(parser, "expected `match` keyword");
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return false;
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}
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struct ivy_ast_match_node *match = create_node(IVY_AST_MATCH);
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if (!parse_expr(parser, EXPR_PARSE_STOP_LEFT_BRACKET, &match->n_cond)) {
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parse_trace(parser, "invalid match predicate");
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return false;
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}
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if (!parse_symbol(parser, IVY_SYM_LEFT_BRACKET)) {
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parse_trace(parser, "expected `[` after match predicate");
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return false;
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}
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bool ok = true;
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while (1) {
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if (parse_symbol(parser, IVY_SYM_RIGHT_BRACKET)) {
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break;
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}
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if (!fx_queue_empty(&match->n_branches)
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&& !parse_symbol(parser, IVY_SYM_COMMA)) {
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parse_trace(
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parser,
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"expected `,` or `]` after match branch value");
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ok = false;
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break;
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}
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struct ivy_ast_node *branch_pred = NULL;
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struct ivy_ast_node *branch_value = NULL;
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if (!parse_expr(parser, EXPR_PARSE_NORMAL, &branch_pred)) {
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parse_trace(parser, "invalid match branch predicate");
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ok = false;
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break;
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}
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if (!parse_symbol(parser, IVY_SYM_EQUAL_RIGHT_ANGLE)) {
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parse_trace(
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parser,
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"expected `=>` after match branch predicate");
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ok = false;
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break;
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}
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if (peek_symbol(parser, IVY_SYM_LEFT_BRACKET)) {
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ok = parse_block(parser, &branch_value);
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} else {
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ok = parse_expr(
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parser, EXPR_PARSE_STOP_COMMA, &branch_value);
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}
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if (!ok) {
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parse_trace(parser, "invalid match branch value");
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break;
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}
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struct ivy_ast_cond_node *cond = create_node(IVY_AST_COND);
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cond->n_cond = branch_pred;
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cond->n_body = branch_value;
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fx_queue_push_back(&match->n_branches, &cond->n_base.n_entry);
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}
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*out = generic_node(match);
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return true;
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}
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