Feature [ASH] Change replace_all, replace_first to return buffers

H

heeheehee

Developer
Staff member
The current state of ASH functions:
Code: 
string replace_all( matcher, string )
string replace_first( matcher, string )
buffer replace_string( buffer, string, string )
buffer replace_string( string, string, string )

The only way to use regular expressions in buffer replacements is via replace_all and replace_first. However, since those return strings, not buffers, we currently need to do something along the lines of
Code: 
buffer body;
...
matcher m = create_matcher(pattern, body);
string s = match.replace_first(replacement_text);
body.set_length(0);
body.append(s);

I would find it more convenient if ASH permitted something like
Code: 
buffer body;
...
matcher m = create_matcher(pattern, body);
body = match.replace_first(replacement_text);
 
Veracity

Veracity

Developer
Staff member
How about:

Code: 
matcher m = create_matcher(pattern, body);
buffer body = match.replace_first(replacement_text).to_buffer();
or even:

Code: 
matcher m = create_matcher(pattern, body);
buffer body = match.replace_first(replacement_text);
... with implicit coercion.

I.e., to_buffer( string) is the inverse of to_string( buffer ).

Otherwise, you are forcing the unnecessary creation of a buffer for whose who want a string.
 
Veracity

Veracity

Developer
Staff member
That's an implementation artifact. Java's Matcher.replaceAll() and Matcher.replaceFirst() take strings and return strings. There is no Java "replaceString", so we call StringUtilities.globalStringReplace which takes a buffer and returns a buffer.

I believe we automatically coerce a buffer into a string, so the caller who doesn't want buffer as the return value never sees it.

If we could auto-coerce both from string to buffer and buffer to string, you wouldn't even care whether any of the functions returned a string vs. a buffer, although the "asymmetry", as you put it, would still exist for the purpose of eliminating unnecessary memory allocation.
 
H

heeheehee

Developer
Staff member
Veracity said:
That's an implementation artifact. Java's Matcher.replaceAll() and Matcher.replaceFirst() take strings and return strings. There is no Java "replaceString", so we call StringUtilities.globalStringReplace which takes a buffer and returns a buffer.
Click to expand...
Makes sense.

I believe we automatically coerce a buffer into a string, so the caller who doesn't want buffer as the return value never sees it.
Click to expand...
Right.

If we could auto-coerce both from string to buffer and buffer to string, you wouldn't even care whether any of the functions returned a string vs. a buffer, although the "asymmetry", as you put it, would still exist for the purpose of eliminating unnecessary memory allocation.
Click to expand...
Also a fair point.

Also, apparently ASH no longer supports to_buffer (as of the great datatype conversion purge of... I don't remember when). Perhaps that would be a more pertinent feature request, in this context?
 
Veracity

Veracity

Developer
Staff member
heeheehee said:
Also, apparently ASH no longer supports to_buffer (as of the great datatype conversion purge of... I don't remember when). Perhaps that would be a more pertinent feature request, in this context?
Click to expand...
I think that would give you what you really want and would also be generally useful elsewhere.

I have no idea why to_buffer() was removed.
 
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