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#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "include/log.h"
#include "include/parser.h"
#include "include/token.h"
// initialize a parser
parser_t* parser_init(lexer_t* lexer) {
parser_t* parser = calloc(1, sizeof(struct PARSER_STRUC));
parser->lexer = lexer;
parser->token = lexer_get_next_token(lexer);
return parser;
}
// check for expected token, or throw syntax error
void parser_check_expect(parser_t* parser, int token_type) {
if (parser->token->type == token_type) {
parser->token = lexer_get_next_token(parser->lexer);
} else {
log_err("Unexpected token");
exit(1);
}
}
// creates the abstract syntax tree
tree_t* parser_parse(parser_t* parser) {
return parser_parse_chunks(parser);
}
tree_t* parser_parse_token_id(parser_t* parser) {
if (strcmp(parser->token->value, "let")) {
return parser_parse_var(parser);
} else { // if id not recognized, check for variables under that name
return parser_parse_var_def(parser);
}
}
// parse a single chunk
tree_t* parser_parse_chunk(parser_t* parser) {
switch (parser->token->type) {
case TOKEN_KEYWORD: {
return parser_parse_keyword(parser);
break;
}
default: {
log_dbg("Skipping non-keyword token");
lexer_next(parser->lexer);
break;
}
}
}
// parse a list of chunks
tree_t* parser_parse_chunks(parser_t* parser) {
tree_t* subtree = tree_init(TREE_SUBTREE);
subtree->data.subtree.val = calloc(1, sizeof(struct TREE_STRUC));
tree_t* chunk = parser_parse_chunk(parser);
subtree->data.subtree.val[0] = chunk;
while (parser->token->type == TOKEN_END) {
parser_check_expect(parser, TOKEN_END);
tree_t* chunk = parser_parse_chunk(parser);
subtree->data.subtree.size += 1;
subtree->data.subtree.val = realloc(
subtree->data.subtree.val,
subtree->data.subtree.size * sizeof(struct TREE_STRUC)
);
subtree->data.subtree.val[subtree->data.subtree.size - 1] = chunk;
}
return subtree;
}
tree_t* parser_parse_expr(parser_t* parser) {
switch (parser->token->type) {
case TOKEN_STR:
parser_parse_str(parser);
break;
default:
log_war("Skipping unknown token");
lexer_next(parser->lexer);
}
};
tree_t* parser_parse_fac(parser_t* parser) {};
tree_t* parser_parse_term(parser_t* parser) {};
tree_t* parser_parse_fn_call(parser_t* parser) {};
tree_t* parser_parse_fn_def(parser_t* parser) {};
tree_t* parser_parse_var(parser_t* parser) {
char* token_val = parser->token->value;
parser_check_expect(parser, TOKEN_KEYWORD); // var name or fn name
// check if function
if (parser->token->type == TOKEN_FN_APPLY) {
return parser_parse_fn_call(parser);
}
tree_t* var = tree_init(TREE_VAR);
var->data.var.name = token_val;
return var;
};
tree_t* parser_parse_var_def(parser_t* parser) {
int var_is_const;
parser_check_expect(parser, TOKEN_KEYWORD); // let
char* var_name = parser->token->value; // set variable name
parser_check_expect(parser, TOKEN_KEYWORD); // expect variable name & advance
if (parser->token->type == TOKEN_DEFINE_CONST) { // check either constant or mutable variable
var_is_const = 1;
parser_check_expect(parser, TOKEN_DEFINE_CONST);
} else {
var_is_const = 0;
parser_check_expect(parser, TOKEN_DEFINE_MUT);
}
tree_t* var_val = parser_parse_expr(parser); // set the value
tree_t* var_def = tree_init(TREE_VAR_DEF); // create the var, as a subtree
var_def->data.var_def.name = var_name;
var_def->data.var_def.val = var_val;
var_def->data.var_def.is_const = &var_is_const;
return var_def;
};
tree_t* parser_parse_str(parser_t* parser) {
log_dbg("Entered str");
tree_t* str = tree_init(TREE_STR);
str->data.str.val = parser->token->value;
parser_check_expect(parser, TOKEN_STR);
return str;
};
tree_t* parser_parse_keyword(parser_t* parser) {
if (strcmp(parser->token->value, "let")) {
return parser_parse_var_def(parser);
} else if (strcmp(parser->token->value, "fn")) {
return parser_parse_fn_def(parser);
} else {
return parser_parse_var(parser); // assume attempting to call
// variable/function;
// TODO: differentiate b/w the
// two on call; may be a syntax
// change :P just to make the
// interpreter easier
}
}
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