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#include <assert.h>
#include <ctype.h>
#include "lex.h"
#define CHAR_COMMENT '#'
static bool source_peek(struct source *src, char *c)
{
if (src->offset >= src->contents.len)
return false;
*c = src->contents.ptr[src->offset];
return true;
}
static void source_next(struct source *src)
{
assert(src->offset < src->contents.len);
src->offset++;
}
static bool source_get(struct source *src, char *c)
{
if (!source_peek(src, c))
return false;
source_next(src);
return true;
}
static void source_unget(struct source *src)
{
assert(src->offset);
src->offset--;
}
static struct range loc_from(struct source *src, size_t start)
{
return (struct range) { .start = start, .end = src->offset };
}
static struct range loc_last(struct source *src)
{
return loc_from(src, src->offset-1);
}
static str str_from(struct source *src, size_t start)
{
return (str) { src->offset - start, src->contents.ptr + start };
}
static bool is_blank_char(char c)
{
return isblank(c) || c == '\n';
}
static bool is_num_start_char(char c)
{
return isdigit(c) || c == '+' || c == '-' || c == '.';
}
static bool is_num_char(char c)
{
return isxdigit(c) || c == '+' || c == '-' || c == '.';
}
static bool is_name_char(char c)
{
return isprint(c) && !is_blank_char(c) && c != CHAR_COMMENT && c != '(' && c != ')';
}
static void source_skip(struct source *src)
{
char c;
while (source_peek(src, &c) && is_blank_char(c))
source_next(src);
if (source_peek(src, &c) && c == CHAR_COMMENT)
while (source_get(src, &c) && c != '\n')
;
}
static str lex_name(struct source *src)
{
size_t start = src->offset;
char c;
while (source_peek(src, &c) && is_name_char(c))
source_next(src);
return str_from(src, start);
}
static str lex_string(struct source *src, size_t start)
{
strbuf buf = { .cap = 32 };
char c;
while (source_get(src, &c)) {
if (c == '\"') {
str s = arraybuf_cast(buf);
arraybuf_insert(&src->strings, s);
return s;
}
// TODO: more escapes
if (c == '\\') {
if (!source_get(src, &c))
source_error(src, loc_last(src), "unterminated escape");
switch (c) {
case '\\':
c = '\\';
break;
case '\"':
c = '\"';
break;
default:
source_error(src, loc_last(src), "unknown escape");
break;
}
}
arraybuf_insert(&buf, c);
}
source_error(src, loc_from(src, start), "unterminated string");
}
static double lex_number(struct source *src)
{
size_t start = src->offset;
char c;
while (source_peek(src, &c) && is_num_char(c))
source_next(src);
double num;
if (!str_parse_double(str_from(src, start), &num))
source_error(src, loc_from(src, start), "invalid number");
return num;
}
enum op_category op_category_tab[] = {
#define OP_TYPE_CAT(name, sym, cat) OPC_##cat,
OP_TYPES(OP_TYPE_CAT)
#undef OP_TYPE_CAT
};
str op_name_tab[] = {
#define OP_TYPE_NAME(name, sym, cat) S(name),
OP_TYPES(OP_TYPE_NAME)
#undef OP_TYPE_NAME
};
static bool lex_op_type(str in_sym, enum op_type *op)
{
if (0) {}
#define OP_TYPE_CASE(sym, name, cat) else if (array_eq(in_sym, S(sym))) { *op = OP_##name; return true; }
OP_TYPES(OP_TYPE_CASE)
#undef OP_TYPE_CASE
else return false;
}
bool lex_token(struct source *src, struct token *tok)
{
source_skip(src);
size_t start = src->offset;
char c;
if (!source_get(src, &c))
return false;
switch (c) {
case '(': {
tok->type = TOKEN_OP;
source_skip(src);
size_t start_name = src->offset;
str name = lex_name(src);
tok->op.name_loc = loc_from(src, start_name);
if (!lex_op_type(name, &tok->op.type))
source_error(src, tok->op.name_loc, "unknown operation");
arraybuf(struct token) children = {};
while ((source_skip(src), !(source_peek(src, &c) && c == ')'))) {
arraybuf_grow(&children, 1);
if (!lex_token(src, &children.ptr[children.len++]))
source_error(src, loc_from(src, start), "unterminated operation");
}
source_next(src);
array_assign(&tok->op.children, children);
break;
}
case '$':
tok->type = TOKEN_VAR;
tok->var = lex_name(src);
break;
case '"':
tok->type = TOKEN_STRING;
tok->string = lex_string(src, start);
break;
default:
source_unget(src);
if (is_num_start_char(c)) {
tok->type = TOKEN_NUMBER;
tok->number = lex_number(src);
} else if (is_name_char(c)) {
tok->type = TOKEN_IDENT;
tok->ident = lex_name(src);
} else {
source_error(src, loc_last(src), "expected token");
}
break;
}
tok->loc = loc_from(src, start);
return true;
}
void free_token(struct token *tok)
{
if (tok->type != TOKEN_OP) return;
for (size_t i = 0; i < tok->op.children.len; i++)
free_token(&tok->op.children.ptr[i]);
free(tok->op.children.ptr);
}
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