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Changed precedence of =>

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This commit is contained in:
Bruce Hill 2021-01-05 19:31:50 -08:00
parent 00226cb763
commit d8d2a5a66e
2 changed files with 38 additions and 37 deletions
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73
compiler.c
View File

@ -56,14 +56,47 @@ static vm_op_t *expand_chain(file_t *f, vm_op_t *first)
}
/*
* Take an opcode and expand it into a chain of choices if it's
* followed by any "/"-separated patterns (e.g. "`x/`y"), otherwise
* return the original input.
* Take an opcode and parse any "=>" replacements and then expand it into a
* chain of choices if it's followed by any "/"-separated patterns (e.g.
* "`x/`y"), otherwise return the original input.
*/
static vm_op_t *expand_choices(file_t *f, vm_op_t *first)
{
first = expand_chain(f, first);
const char *str = first->end;
while (str+2 < f->end && matchstr(&str, "=>")) { // Replacement <pat> => <pat>
str = after_spaces(str);
char quote = *str;
if (!(matchchar(&str, '"') || matchchar(&str, '\'')))
file_err(f, str, str, "There should be a string literal as a replacement here.");
const char *repstr = str;
for (; *str && *str != quote; str++) {
if (*str == '\\') {
if (!str[1] || str[1] == '\n')
file_err(f, str, str+1,
"There should be an escape sequence after this backslash.");
++str;
}
}
if (!matchchar(&str, quote))
file_err(f, &repstr[-1], str, "This string doesn't have a closing quote.");
size_t replace_len = (size_t)(str-repstr-1);
const char *replacement = xcalloc(sizeof(char), replace_len+1);
memcpy((void*)replacement, repstr, replace_len);
vm_op_t *pat = first;
first = new(vm_op_t);
first->op = VM_REPLACE;
first->args.replace.pat = pat;
first->args.replace.text = replacement;
first->args.replace.len = replace_len;
first->len = pat->len;
first->start = pat->start;
first->end = str;
}
if (!matchchar(&str, '/')) return first;
vm_op_t *second = bp_simplepattern(f, str);
if (!second)
@ -430,39 +463,7 @@ vm_op_t *bp_simplepattern(file_t *f, const char *str)
// Postfix operators:
postfix:
str = after_spaces(str);
if (str+2 < f->end && matchstr(&str, "=>")) { // Replacement <pat> => <pat>
str = after_spaces(str);
char quote = *str;
if (!(matchchar(&str, '"') || matchchar(&str, '\'')))
file_err(f, str, str, "There should be a string literal as a replacement here.");
const char *repstr = str;
for (; *str && *str != quote; str++) {
if (*str == '\\') {
if (!str[1] || str[1] == '\n')
file_err(f, str, str+1,
"There should be an escape sequence after this backslash.");
++str;
}
}
if (!matchchar(&str, quote))
file_err(f, &repstr[-1], str, "This string doesn't have a closing quote.");
size_t replace_len = (size_t)(str-repstr-1);
const char *replacement = xcalloc(sizeof(char), replace_len+1);
memcpy((void*)replacement, repstr, replace_len);
vm_op_t *pat = op;
op = new(vm_op_t);
op->op = VM_REPLACE;
op->args.replace.pat = pat;
op->args.replace.text = replacement;
op->args.replace.len = replace_len;
op->len = pat->len;
op->start = pat->start;
op->end = str;
goto postfix;
} else if (str+2 < f->end && (matchstr(&str, "!=") || matchstr(&str, "=="))) { // Equality <pat1>==<pat2> and inequality <pat1>!=<pat2>
if (str+2 < f->end && (matchstr(&str, "!=") || matchstr(&str, "=="))) { // Equality <pat1>==<pat2> and inequality <pat1>!=<pat2>
int equal = str[-2] == '=';
vm_op_t *first = op;
vm_op_t *second = bp_simplepattern(f, str);

2
grammars/bpeg.bp
View File

@ -34,7 +34,7 @@ Char: (@s=. / @!=(''=> "Expected a character following the '`'"))
Escape-range: `\ @low=escape-sequence `- @high=escape-sequence
Escape: `\ (@s=escape-sequence
/ $ @!=(''=>"Backslashes are used for escape sequences, not splitting lines")
/ @!=((. *(Abc/`0-9)) => "Invalid escape sequence: '@0'")
/ @!=(. *(Abc/`0-9) => "Invalid escape sequence: '@0'")
)
escape-sequence: (
`n,t,r,e,b,a,v