VIM and Solving a More Complex Lower-case'ing

The problem was looking painful. I needed to lower case parts of about 130 lines of code. But only part of each given line. tr and/or sed are my normal tools of choice for such a beastie, but I wasn't sure I could convince either to only hit the section I wanted.

Basically, I had:

    const char *kwords[] = { "Undefined",       /* 0 = undefined keyword       0  */
        "OutputDir",                            /* Output directory            1  */
        "LogFile",                              /* Log file to use for input   2  */
        "ReportTitle",                          /* Title for reports           3  */
        "HostName",                             /* Hostname to use             4  */
        ...

and wanted:

    const char *kwords[] = { "undefined",       /* 0 = undefined keyword       0  */
        "outputdir",                            /* Output directory            1  */
        "logfile",                              /* Log file to use for input   2  */
        "reporttitle",                          /* Title for reports           3  */
        "hostname",                             /* Hostname to use             4  */
        ...

Tricky. Or so I initially thought. I'd just about resigned myself to 15 minutes of terminal boredom manually editing this when my quick reading of the vim help (:help replace) led me to being able to construct this relatively simple one liner fix:

  :'a,'bs/"\([A-Za-z0-9]*\)"/"\L\1\E"/

Or in English:

• Preparation: Mark a & b, being the start and end you wish to process.
• So: From Mark a ('a) to Mark b ('b) do a search and replace
• Search for A-Z, a-z and 0-9 characters, alnum's basically, enclosed in double quotes. Keeping track of the text in the quotes ( \(...\) )
• Replace with the double quotes we found. &
• Lower-case (\L) the found text (\1) only (\E - delimits the end of \L)

Too Easy.

Incidentally, this also means I've managed to somewhat simply implement case insensitivity into the AWFFull config file processing. At long last. Hurrah!