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#include "parser_internal.h"
//
// general case: parse sequence, pick one result
//
typedef struct {
const HParser **parsers;
size_t count; // how many parsers in 'ps'
size_t which; // whose result to return
} HIgnoreSeq;
static HParseResult* parse_ignoreseq(void* env, HParseState *state) {
const HIgnoreSeq *seq = (HIgnoreSeq*)env;
HParseResult *res = NULL;
for (size_t i=0; i < seq->count; ++i) {
HParseResult *tmp = h_do_parse(seq->parsers[i], state);
if (!tmp)
return NULL;
else if (i == seq->which)
res = tmp;
}
return res;
}
static const HParserVtable ignoreseq_vt = {
.parse = parse_ignoreseq,
};
//
// API frontends
//
static const HParser* h_leftright(const HParser* p, const HParser* q, size_t which) {
HIgnoreSeq *seq = g_new(HIgnoreSeq, 1);
seq->parsers = g_new(const HParser*, 2);
seq->parsers[0] = p;
seq->parsers[1] = q;
seq->count = 2;
seq->which = which;
HParser *ret = g_new(HParser, 1);
ret->vtable = &ignoreseq_vt;
ret->env = (void*)seq;
return ret;
}
const HParser* h_left(const HParser* p, const HParser* q) {
return h_leftright(p, q, 0);
}
const HParser* h_right(const HParser* p, const HParser* q) {
return h_leftright(p, q, 1);
}
const HParser* h_middle(const HParser* p, const HParser* x, const HParser* q) {
HIgnoreSeq *seq = g_new(HIgnoreSeq, 1);
seq->parsers = g_new(const HParser*, 3);
seq->parsers[0] = p;
seq->parsers[1] = x;
seq->parsers[2] = q;
seq->count = 3;
seq->which = 1;
HParser *ret = g_new(HParser, 1);
ret->vtable = &ignoreseq_vt;
ret->env = (void*)seq;
return ret;
}