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doc: Document %strcat

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H. Peter Anvin 2008-07-13 15:35:07 -07:00
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doc/nasmdoc.src
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@ -2175,19 +2175,40 @@ This can be used, for example, with the \c{%!} construct (see
\c %defstr PATH %!PATH ; The operating system PATH variable
\H{strlen} \i{String Handling in Macros}: \i\c{%strlen} and \i\c{%substr}
\H{strlen} \i{String Manipulation in Macros}
It's often useful to be able to handle strings in macros. NASM
supports two simple string handling macro operators from which
more complex operations can be constructed.
All the string operators define or redefine a value (either a string
or a numeric value) to a single-line macro.
\S{strcat} \i{Concatenating Strings}: \i\c{%strcat}
The \{%strcat} operator concatenates quoted strings and assign them to
a single-line macro. In doing so, it may change the type of quotes
and possibly use \c{\}-escapes inside \c{`}-quoted strings in order to
make sure the string is still a valid quoted string.
For example:
\c %strcat alpha "Alpha: ", '12" screen'
... would assign the value \c{'Alpha: 12" screen'} to \c{alpha}.
Similarly:
\c %strcat beta '"', "'"
... would assign the value \c{`"'`} to \c{beta}.
The use of commas to separate strings are permitted but optional.
\S{strlen} \i{String Length}: \i\c{%strlen}
The \c{%strlen} macro is like \c{%assign} macro in that it creates
(or redefines) a numeric value to a macro. The difference is that
with \c{%strlen}, the numeric value is the length of a string. An
example of the use of this would be:
The \c{%strlen} operator assigns the length of a string to a macro.
For example:
\c %strlen charcnt 'my string'
@ -2203,10 +2224,11 @@ As in the first case, this would result in \c{charcnt} being
assigned the value of 9.
\S{substr} \i{Sub-strings}: \i\c{%substr}
\S{substr} \i{Extracting Substrings}: \i\c{%substr}
Individual letters in strings can be extracted using \c{%substr}.
An example of its use is probably more useful than the description:
Individual letters or substrings in strings can be extracted using the
\c{%substr} operator. An example of its use is probably more useful
than the description:
\c %substr mychar 'xyzw' 1 ; equivalent to %define mychar 'x'
\c %substr mychar 'xyzw' 2 ; equivalent to %define mychar 'y'