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Crystal pipe working with module prefixes
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# this was copied from https://carc.in/#/r/fg2 | |
# thanks to @waterlink from this issue thread https://github.com/crystal-lang/crystal/issues/1388 | |
module CrChainableMethods | |
module Pipe | |
macro pipe(ast) | |
{% uast = ast.stringify.gsub(/ >>/, ".pipe").id %} | |
{% pp uast %} | |
{% if uast.stringify != ast.stringify %} | |
pipe {{uast}} | |
{% else %} | |
{% if ast.name.id == "pipe".id %} | |
{% if ast.args.first.receiver.is_a?(Nop) %} | |
{{ast.args.first.name}}({{ast.receiver}}, {{ast.args.first.args.argify}}) | |
{% else %} | |
{% receiver_name = ast.args.first.receiver.stringify.gsub(/\(.*\)/, "").id %} | |
pipe {{receiver_name}}({{ast.receiver}}, {{ast.args.first.receiver.args.argify}}).pipe {{ast.args.first.args.argify}} | |
{% end %} | |
{% else %} | |
{{ast}} | |
{% end %} | |
{% end %} | |
end | |
macro included | |
#FIXME this should be used as the last call in the chain if the previous call explicitly calls from a module such as: | |
# .>> Foo.method .>> unwrap | |
# Still don't know why the ast parsing works ok for just .>> method but fails for .>> Foo.method | |
def self.unwrap(foo) | |
foo | |
end | |
end | |
end | |
end | |
include CrChainableMethods::Pipe | |
module Foo | |
def self.split_words(phrase) | |
phrase.split(" ") | |
end | |
def self.append_message(words, message) | |
words + [message] | |
end | |
def self.join(words) | |
words.join(" - ") | |
end | |
end | |
module Bar | |
def self.add_something(words) | |
words + ["something"] | |
end | |
end | |
result = pipe "Hello World" | |
.>> Foo.split_words | |
.>> Foo.append_message("Bar") | |
.>> Bar.add_something | |
.>> Foo.join | |
.>> unwrap | |
puts result |
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