17.4.1 @set and @value

You use the @set command to specify a value for a flag, which is later expanded by the @value command.

A flag (aka variable) is an identifier. It is best to use only letters and numerals in a flag name, not `-' or `_'—they will work in some contexts, but not all, due to limitations in TeX.

The value is the remainder of the input line, and can contain anything.

Write the @set command like this:

     @set foo This is a string.

This sets the value of the flag foo to “This is a string.”.

The Texinfo formatters then replace an @value{flag} command with the string to which flag is set. Thus, when foo is set as shown above, the Texinfo formatters convert this:

     @value{foo}

to this:

     This is a string.

You can write an @value command within a paragraph; but you must write an @set command on a line of its own.

If you write the @set command like this:

     @set foo

without specifying a string, the value of foo is the empty string.

If you clear a previously set flag with @clear flag, a subsequent @value{flag} command will report an error.

For example, if you set foo as follows:

     @set howmuch very, very, very

then the formatters transform

     It is a @value{howmuch} wet day.

into

     It is a very, very, very wet day.

If you write

     @clear howmuch

then the formatters transform

     It is a @value{howmuch} wet day.

into

     It is a {No value for "howmuch"} wet day.