e3d2e555ae
Fix some mistakes in comments. Improve some comments to be easier understandable. Inline variables that are irrelevant for the test at hand (RUN, MAKE_CMD). Remove references to functions and constants that have since been removed or renamed.
138 lines
3.5 KiB
Makefile
138 lines
3.5 KiB
Makefile
# $NetBSD: cond-func.mk,v 1.9 2020/11/15 14:07:53 rillig Exp $
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#
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# Tests for those parts of the functions in .if conditions that are common
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# among several functions.
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#
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# The below test uses the function defined(...) since it has no side-effects,
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# the other functions (except empty(...)) would work equally well. The
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# function empty is special because it uses a different parsing algorithm for
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# its argument.
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DEF= defined
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${:UA B}= variable name with spaces
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${:UVAR(value)}= variable name with parentheses
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${:UVAR{value}}= variable name with balanced braces
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# Really strange variable names must be given indirectly via another variable,
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# so that no unbalanced braces appear in the top-level expression.
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VARNAME_UNBALANCED_BRACES= VAR{{{value
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${VARNAME_UNBALANCED_BRACES}= variable name with unbalanced braces
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.if !defined(DEF)
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. error
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.endif
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# Horizontal whitespace (space tab) after the opening parenthesis is ignored.
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.if !defined( DEF)
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. error
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.endif
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# Horizontal whitespace (space tab) before the closing parenthesis is ignored.
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.if !defined(DEF )
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. error
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.endif
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# The argument of a function must not directly contain whitespace.
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.if !defined(A B)
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. error
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.endif
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# If necessary, the whitespace can be generated by a variable expression.
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.if !defined(${:UA B})
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. error
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.endif
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# Characters that could be mistaken for operators must not appear directly
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# in a function argument. As with whitespace, these can be generated
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# indirectly.
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#
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# It's not entirely clear why these characters are forbidden.
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# The most plausible reason seems to be typo detection.
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.if !defined(A&B)
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. error
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.endif
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.if !defined(A|B)
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. error
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.endif
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# Even parentheses may appear in variable names.
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# They must be balanced though.
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.if !defined(VAR(value))
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. error
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.endif
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# Braces do not have any special meaning when parsing arguments.
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.if !defined(VAR{value})
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. error
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.endif
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# Braces do not have any special meaning when parsing arguments.
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# They don't need to be balanced.
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.if !defined(VAR{{{value)
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. error
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.endif
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# There may be spaces around the operators and parentheses, and even
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# inside the parentheses. The spaces inside the parentheses are not
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# allowed for the empty() function (see cond-func-empty.mk), therefore
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# they are typically omitted for the other functions as well.
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.if ! defined ( DEF )
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. error
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.endif
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# The following condition is interpreted as defined(A) && defined(B).
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# In lack of a function call expression, each kind of .if directive has a
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# default function that is called when a bare word is parsed. For the plain
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# .if directive, this function is defined(); see "struct If ifs" in cond.c.
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.if A&B
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. error
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.endif
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.if defined()
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. error
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.else
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. info The empty variable is never defined.
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.endif
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# The plain word 'defined' is interpreted as '!empty(defined)'.
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# That variable is not defined (yet).
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.if defined
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. error
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.else
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. info A plain function name is parsed as !empty(...).
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.endif
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# If a variable named 'defined' is actually defined and not empty, the plain
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# symbol 'defined' evaluates to true.
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defined= non-empty
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.if defined
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. info A plain function name is parsed as !empty(...).
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.else
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. error
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.endif
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# A plain symbol name may start with one of the function names, in this case
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# 'defined'.
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.if defined-var
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. error
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.else
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. info Symbols may start with a function name.
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.endif
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defined-var= non-empty
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.if defined-var
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. info Symbols may start with a function name.
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.else
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. error
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.endif
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# Missing closing parenthesis when parsing the function argument.
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.if defined(
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. error
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.else
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. error
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.endif
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all:
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@:;
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