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Deal with Makefile conditional assignment operators.

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Ordinarily variable assignments in Makefiles are done simply with an
unconditional assignment: the equals sign.  There are variants of this:

FOO := $(BAR)	Avoid recursively expand variables.
FOO ?= bar	Assign only if $(FOO) is not already set.
FOO += bar	Add more to a variable.
FOO != bar	Execute a shell script and assign result to $(FOO).

See also
https://www.gnu.org/software/make/manual/html_node/Conditional-Example.html
https://www.gnu.org/software/make/manual/html_node/Flavors.html
This commit is contained in:
David Griffith 2019-10-20 17:14:48 -07:00 committed by Mike McQuaid
parent 253e45bb94
commit 6ff61909a9
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1 changed files with 5 additions and 3 deletions
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8
Library/Homebrew/extend/string.rb
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@ -41,7 +41,7 @@ module StringInreplaceExtension
# Looks for Makefile style variable definitions and replaces the
# value with "new_value", or removes the definition entirely.
def change_make_var!(flag, new_value)
return if gsub!(/^#{Regexp.escape(flag)}[ \t]*=[ \t]*(.*)$/, "#{flag}=#{new_value}", false)
return if gsub!(/^#{Regexp.escape(flag)}[ \t]*[\\?\+\:\!]?=[ \t]*(.*)$/, "#{flag}=#{new_value}", false)
errors << "expected to change #{flag.inspect} to #{new_value.inspect}"
end
@ -50,12 +50,14 @@ module StringInreplaceExtension
def remove_make_var!(flags)
Array(flags).each do |flag|
# Also remove trailing \n, if present.
errors << "expected to remove #{flag.inspect}" unless gsub!(/^#{Regexp.escape(flag)}[ \t]*=.*$\n?/, "", false)
if gsub!(/^#{Regexp.escape(flag)}[ \t]*[\\?\+\:\!]?=.*$\n?/, "", false)
errors << "expected to remove #{flag.inspect}"
end
end
end
# Finds the specified variable
def get_make_var(flag)
self[/^#{Regexp.escape(flag)}[ \t]*=[ \t]*(.*)$/, 1]
self[/^#{Regexp.escape(flag)}[ \t]*[\\?\+\:\!]?=[ \t]*(.*)$/, 1]
end
end