75 lines
1.8 KiB
Makefile
Executable File
75 lines
1.8 KiB
Makefile
Executable File
# $NetBSD: cond-cmp-unary.mk,v 1.3 2022/09/08 05:43:20 rillig Exp $
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#
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# Tests for unary comparisons in .if conditions, that is, comparisons with
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# a single operand. If the operand is a number, it is compared to zero,
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# if it is a string, it is tested for emptiness.
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# The number 0 in all its various representations evaluates to false.
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.if 0 || 0.0 || 0e0 || 0.0e0 || 0.0e10
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. error
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.endif
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# Any other number evaluates to true.
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.if !12345
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. error
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.endif
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# The empty string evaluates to false.
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.if ""
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. error
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.endif
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# Any other string evaluates to true.
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.if !"0"
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. error
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.endif
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# The empty string may come from a variable expression.
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#
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# XXX: As of 2020-11-11, this empty string is interpreted "as a number" in
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# EvalNotEmpty, which is plain wrong. The bug is in TryParseNumber.
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.if ${:U}
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. error
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.endif
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# A variable expression that is not surrounded by quotes is interpreted
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# as a number if possible, otherwise as a string.
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.if ${:U0}
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. error
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.endif
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# A non-zero number from a variable expression evaluates to true.
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.if !${:U12345}
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. error
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.endif
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# A string of whitespace should evaluate to false.
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#
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# XXX: As of 2020-11-11, the implementation in EvalNotEmpty does not skip
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# whitespace before testing for the end. This was probably an oversight in
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# a commit from 1992-04-15 saying "A variable is empty when it just contains
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# spaces".
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.if ${:U }
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. info This is only reached because of a bug in EvalNotEmpty.
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.else
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. error
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.endif
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# The condition '${VAR:M*}' is almost equivalent to '${VAR:M*} != ""'. The
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# only case where they differ is for a single word whose numeric value is zero.
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.if ${:U0:M*}
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. error
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.endif
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.if ${:U0:M*} == ""
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. error
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.endif
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# Multiple words cannot be parsed as a single number, thus evaluating to true.
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.if !${:U0 0:M*}
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. error
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.endif
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.if ${:U0 0:M*} == ""
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. error
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.endif
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all: # nothing
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