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#include "parser.h"
#include "config.h"
#include "tokenizer.h"
typedef struct {
SandTokenizer tokenizer;
SandToken previous;
SandToken current;
SandAllocator *a;
SandState *S;
} Parser;
// Report an error at the given token and enter panic mode.
static void error_at(Parser *parser, SandToken token, const char *message) {
sand_print_diagnostic(parser->S, token.location, SAND_DIAGNOSTIC_ERROR, "");
}
// Same as `error_at` except using the parser's current token.
static void error_at_current(Parser *parser, const char *message) {
error_at(parser, parser->current, message);
}
static void advance(Parser *parser) {
parser->previous = parser->current;
while (true) {
parser->current = sand_get_next_token(&parser->tokenizer);
if (parser->current.kind == SAND_TOKEN_ERROR) {
// `content` is going to be NULL-terminated because it will always point to a C string literal for error tokens.
error_at_current(parser, parser->current.content);
} else {
break;
}
}
}
static SandToken peek(const Parser *parser) {
return parser->current;
}
static bool match(Parser *parser, SandTokenKind expected) {
if (peek(parser).kind == expected) {
advance(parser);
return true;
} else {
return false;
}
}
static void consume(Parser *parser, SandTokenKind expected, const char *error) {
if (!match(parser, expected)) {
error_at_current(parser, error);
}
}
SandAst *sand_parse(SandState *S, SandAllocator *a, const char *source, size_t source_length, const char *filename) {
Parser parser;
parser.a = a;
parser.S = S;
parser.tokenizer = sand_create_tokenizer(source, source_length, filename);
advance(&parser); // Prime the pump on the tokenizer.
// Parse the document.
SandAst *expr = expression(&parser);
consume(&parser, SAND_TOKEN_EOF, "Expected end of expression");
return expr;
}
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