2c3632d14f
Lots of code refactoring, simplification and cleanup. Lots of new unit-tests providing much higher code coverage. All courtesy of rillig at netbsd. Other significant changes: o new read-only variable .SHELL which provides the path of the shell used to run scripts (as defined by the .SHELL target). o variable parsing detects more errors. o new debug option -dl: LINT mode, does the equivalent of := for all variable assignments so that file and line number are reported for variable parse errors.
30 lines
1019 B
Makefile
30 lines
1019 B
Makefile
# $NetBSD: cond-late.mk,v 1.2 2020/07/25 20:37:46 rillig Exp $
|
|
#
|
|
# Using the :? modifier, variable expressions can contain conditional
|
|
# expressions that are evaluated late. Any variables appearing in these
|
|
# conditions are expanded before parsing the condition. This is
|
|
# different from many other places.
|
|
#
|
|
# Because of this, variables that are used in these lazy conditions
|
|
# should not contain double-quotes, or the parser will probably fail.
|
|
#
|
|
# They should also not contain operators like == or <, since these are
|
|
# actually interpreted as these operators. This is demonstrated below.
|
|
#
|
|
# If the order of evaluation were to change to first parse the condition
|
|
# and then expand the variables, the output would change from the
|
|
# current "yes no" to "yes yes", since both variables are non-empty.
|
|
|
|
all: cond-literal
|
|
|
|
COND.true= "yes" == "yes"
|
|
COND.false= "yes" != "yes"
|
|
|
|
cond-literal:
|
|
@echo ${ ${COND.true} :?yes:no}
|
|
@echo ${ ${COND.false} :?yes:no}
|
|
|
|
VAR+= ${${UNDEF} != "no":?:}
|
|
.if empty(VAR:Mpattern)
|
|
.endif
|