Home | History | Annotate | Line # | Download | only in unit-tests
varmod-defined.mk revision 1.8 
      1 # $NetBSD: varmod-defined.mk,v 1.8 2020/11/08 20:29:13 rillig Exp $
      2 #
      3 # Tests for the :D variable modifier, which returns the given string
      4 # if the variable is defined.  It is closely related to the :U modifier.
      5 
      6 DEF=	defined
      7 .undef UNDEF
      8 
      9 # Since DEF is defined, the value of the expression is "value", not
     10 # "defined".
     11 #
     12 .if ${DEF:Dvalue} != "value"
     13 .  error
     14 .endif
     15 
     16 # Since UNDEF is not defined, the "value" is ignored.  Instead of leaving the
     17 # expression undefined, it is set to "", exactly to allow the expression to
     18 # be used in .if conditions.  In this place, other undefined expressions
     19 # would generate an error message.
     20 # XXX: Ideally the error message would be "undefined variable", but as of
     21 # 2020-08-25 it is "Malformed conditional".
     22 #
     23 .if ${UNDEF:Dvalue} != ""
     24 .  error
     25 .endif
     26 
     27 # The modifier text may contain plain text as well as expressions.
     28 #
     29 .if ${DEF:D<${DEF}>} != "<defined>"
     30 .  error
     31 .endif
     32 
     33 # Special characters that would be interpreted differently can be escaped.
     34 # These are '}' (the closing character of the expression), ':', '$' and '\'.
     35 # Any other backslash sequences are preserved.
     36 #
     37 # The escaping rules for string literals in conditions are completely
     38 # different though. There, any character may be escaped using a backslash.
     39 #
     40 .if ${DEF:D \} \: \$ \\ \) \n } != " } : \$ \\ \\) \\n "
     41 .  error
     42 .endif
     43 
     44 # Like in several other places in variable expressions, when
     45 # ApplyModifier_Defined calls Var_Parse, double dollars lead to a parse
     46 # error that is silently ignored.  This makes all dollar signs disappear,
     47 # except for the last, which is a well-formed variable expression.
     48 #
     49 .if ${DEF:D$$$$$${DEF}} != "defined"
     50 .  error
     51 .endif
     52 
     53 # Any other text is written without any further escaping.  In contrast
     54 # to the :M modifier, parentheses and braces do not need to be nested.
     55 # Instead, the :D modifier is implemented sanely by parsing nested
     56 # expressions as such, without trying any shortcuts. See ApplyModifier_Match
     57 # for an inferior variant.
     58 #
     59 .if ${DEF:D!&((((} != "!&(((("
     60 .  error
     61 .endif
     62 
     63 # The :D modifier is often used in combination with the :U modifier.
     64 # It does not matter in which order the :D and :U modifiers appear.
     65 .if ${UNDEF:Dyes:Uno} != no
     66 .  error
     67 .endif
     68 .if ${UNDEF:Uno:Dyes} != no
     69 .  error
     70 .endif
     71 .if ${DEF:Dyes:Uno} != yes
     72 .  error
     73 .endif
     74 .if ${DEF:Uno:Dyes} != yes
     75 .  error
     76 .endif
     77 
     78 # Since the variable with the empty name is never defined, the :D modifier
     79 # can be used to add comments in the middle of an expression.  That
     80 # expression always evaluates to an empty string.
     81 .if ${:D This is a comment. } != ""
     82 .  error
     83 .endif
     84 
     85 # TODO: Add more tests for parsing the plain text part, to cover each branch
     86 # of ApplyModifier_Defined.
     87 
     88 # The :D and :U modifiers behave differently from the :@var@ modifier in
     89 # that they preserve dollars in a ':=' assignment.  This is because
     90 # ApplyModifier_Defined passes the eflags unmodified to Var_Parse, unlike
     91 # ApplyModifier_Loop, which uses ParseModifierPart, which in turn removes
     92 # VARE_KEEP_DOLLAR from eflags.
     93 #
     94 # XXX: This inconsistency is documented nowhere.
     95 .MAKEFLAGS: -dv
     96 8_DOLLARS=	$$$$$$$$
     97 VAR:=		${8_DOLLARS}
     98 VAR:=		${VAR:D${8_DOLLARS}}
     99 VAR:=		${VAR:@var@${8_DOLLARS}@}
    100 .MAKEFLAGS: -d0
    101 
    102 all:
    103 	@:;
    104