Re: [Spirit-general] Compilation has become very slow after adding rule ID's

[Carl B. <cb...@ad...>]

On Mar 21, 2007, at 12:05 AM, Steve Drake wrote:

> I am working on a program to parse C source files. I took the C=20
> grammar from the repository and modified it to add some leaf_node[]=20
> constructs and am parsing it using pt_parse(). When I added ID's to=20
> the rules, such as below, the compilation of the program slowed to a=20=

> virtual halt:
> =A0
> =A0=A0 enum
> =A0=A0 {
> =A0=A0=A0=A0=A0 // operators
> =A0=A0=A0=A0=A0 eRuleIdLeftBrace,
> =A0=A0=A0=A0=A0 eRuleIdRightBrace,
> =A0=A0=A0=A0=A0=A0...
> =A0=A0=A0};
> =A0
> =A0=A0 ...
>
> =A0=A0 rule< ScannerT, parser_context<>, =
parser_tag<eRuleIdLeftBrace=A0=A0=A0 >=20
> >=A0=A0 LEFT_BRACE;
> =A0=A0 rule< ScannerT, parser_context<>, =
parser_tag<eRuleIdRightBrace=A0=A0 >=20
> >=A0=A0 RIGHT_BRACE;
> What used to compile in a reasonable time (maybe a minute or two?) now=20=

> takes so long that I have finally aborted the build after 1.5 HOURS!=20=

> My PC is not especially fast (Pentium 4 1.7 GHz with 256MB RAM) but=20
> I've never had anything take this long. The compile seems to want a=20
> lot of RAM so I ordered another 512MB to see if that would help but I=20=

> am not optimistic.
> =A0
> Have I done something incredibly stupid? (I wouldn't put it past=20
> myself.) The reason I added the ID's is so that I could traverse the=20=

> generated parse tree looking for certain constructs (such as=20
> identifiers).
> =A0
> The source code is in the attached ZIP file (rename the file extension=20=

> to .zip).
> =A0
> I am compiling on Windows 2000 with gcc 3.4.2.
> =A0
> Thanks in advance for any advice!
>
   The big problem is you have 127 different instances of the template=20=

rule< ...>.
because you gave everything a tag.  Reduce the # of tags to what is=20
important
for your traversal,  Eliminating   A =3D str_p("if") ; rules reduces the=20=

template 'space' as well.

reducing the tags reduces the compiler 'space' needed:)

  might also make compile time more managable as well.