49 lines
1.8 KiB
Plaintext
49 lines
1.8 KiB
Plaintext
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YAPP is a simple macro preprocessor designed to do minor tweaking to
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another program's inputs.
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In its input, anything of the form ${foo} is expanded with the variable
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named foo. It is an error if ${foo} is not defined.
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If you need to escape a dollar sign for some reason, the variable
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with the empty string name , ${}, has the value "$".
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The result of macro expansion is *not* re-expanded. Expansion is done only
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when definitions are made.
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After variable expansion, lines are checked to see if they are control lines.
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Control lines begin with ## (after optional leading whitespace) All such lines are deleted and
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do not appear in the output. ### is a comment. Other options
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are:
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##set variable=value
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value may have one of the following forms:
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token: Trailing whitespace is stripped. The token may not contain
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any whitespace. Use quotes if it's complicated.
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"string": The string may have embedded quotes, and whitespace after
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the closing quote.
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<<"DELIM": This is a here-document, and the value is all of the following
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lines up until, but not including, the newline that precedes a line
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that consists soley of DELIM, for any DELIM string.
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The Delim must be in quotes. You have two options:
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"DELIM": Expand macros in the body of the here-document.
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'DELIM': Do not expand macros in the here-document.
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##include "filename": Insert the named file in place of the current line.
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##if num == num
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##if num != num
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##if num < num
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##if num > num
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##if num <= num
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##if num >= num
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##if token eq token
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##if token ne token
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##ifdef symbol
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##ifndef symbol
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##else
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##endif
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You can figure this one out. Macros in between are expanded as usual
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(so the ##else or ##endif may be in a macro expansion), but the result
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is ignored. String comparison is allowed only between simple words.
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#ifdef symbol is true if ${symbol} is defined.
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