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support hex escapes in string literals

master
Andrew Kelley 2016-04-08 17:30:26 -07:00
parent 491e3cb5c5
commit 73c814e5c0
2 changed files with 117 additions and 34 deletions
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145
src/parser.cpp
View File

@ -223,6 +223,42 @@ static uint8_t parse_char_literal(ParseContext *pc, Token *token) {
return return_value;
}
static int get_hex_digit(uint8_t c) {
switch (c) {
case '0': return 0;
case '1': return 1;
case '2': return 2;
case '3': return 3;
case '4': return 4;
case '5': return 5;
case '6': return 6;
case '7': return 7;
case '8': return 8;
case '9': return 9;
case 'a':
case 'A':
return 10;
case 'b':
case 'B':
return 11;
case 'c':
case 'C':
return 12;
case 'd':
case 'D':
return 13;
case 'e':
case 'E':
return 14;
case 'f':
case 'F':
return 15;
default:
return -1;
}
}
static void parse_string_literal(ParseContext *pc, Token *token, Buf *buf, bool *out_c_str,
ZigList<SrcPos> *offset_map)
{
@ -240,12 +276,22 @@ static void parse_string_literal(ParseContext *pc, Token *token, Buf *buf, bool
// convert escape sequences
// detect c string literal
enum State {
StateStart,
StateEscape,
StateHex1,
StateHex2,
};
buf_resize(buf, 0);
bool escape = false;
State state = StateStart;
bool skip_quote;
SrcPos pos = {token->start_line, token->start_column};
int hex_value = 0;
for (int i = token->start_pos; i < token->end_pos - 1; i += 1) {
uint8_t c = *((uint8_t*)buf_ptr(pc->buf) + i);
if (i == token->start_pos) {
skip_quote = (c == 'c');
if (out_c_str) {
@ -256,41 +302,72 @@ static void parse_string_literal(ParseContext *pc, Token *token, Buf *buf, bool
} else if (skip_quote) {
skip_quote = false;
} else {
if (escape) {
switch (c) {
case '\\':
buf_append_char(buf, '\\');
switch (state) {
case StateStart:
if (c == '\\') {
state = StateEscape;
} else {
buf_append_char(buf, c);
if (offset_map) offset_map->append(pos);
}
break;
case StateEscape:
switch (c) {
case '\\':
buf_append_char(buf, '\\');
if (offset_map) offset_map->append(pos);
state = StateStart;
break;
case 'r':
buf_append_char(buf, '\r');
if (offset_map) offset_map->append(pos);
state = StateStart;
break;
case 'n':
buf_append_char(buf, '\n');
if (offset_map) offset_map->append(pos);
state = StateStart;
break;
case 't':
buf_append_char(buf, '\t');
if (offset_map) offset_map->append(pos);
state = StateStart;
break;
case '"':
buf_append_char(buf, '"');
if (offset_map) offset_map->append(pos);
state = StateStart;
break;
case 'x':
state = StateHex1;
break;
default:
ast_error(pc, token, "invalid escape character");
break;
}
break;
case StateHex1:
{
int hex_digit = get_hex_digit(c);
if (hex_digit == -1) {
ast_error(pc, token, "invalid hex digit: '%c'", c);
}
hex_value = hex_digit * 16;
state = StateHex2;
break;
case 'r':
buf_append_char(buf, '\r');
if (offset_map) offset_map->append(pos);
}
case StateHex2:
{
int hex_digit = get_hex_digit(c);
if (hex_digit == -1) {
ast_error(pc, token, "invalid hex digit: '%c'", c);
}
hex_value += hex_digit;
assert(hex_value >= 0 && hex_value <= 255);
buf_append_char(buf, hex_value);
state = StateStart;
break;
case 'n':
buf_append_char(buf, '\n');
if (offset_map) offset_map->append(pos);
break;
case 't':
buf_append_char(buf, '\t');
if (offset_map) offset_map->append(pos);
break;
case '"':
buf_append_char(buf, '"');
if (offset_map) offset_map->append(pos);
break;
case 'x':
zig_panic("TODO");
break;
default:
ast_error(pc, token, "invalid escape character");
break;
}
escape = false;
} else if (c == '\\') {
escape = true;
} else {
buf_append_char(buf, c);
if (offset_map) offset_map->append(pos);
}
}
}
if (c == '\n') {
@ -300,7 +377,7 @@ static void parse_string_literal(ParseContext *pc, Token *token, Buf *buf, bool
pos.column += 1;
}
}
assert(!escape);
assert(state == StateStart);
if (offset_map) offset_map->append(pos);
}

6
test/self_hosted.zig
View File

@ -560,3 +560,9 @@ fn call_fn_with_empty_string() {
}
fn accepts_string(foo: []u8) { }
#attribute("test")
fn hex_escape() {
assert(str_eql("\x68\x65\x6c\x6c\x6f", "hello"));
}