57 lines
1.8 KiB
Ruby
57 lines
1.8 KiB
Ruby
require "docile/version"
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require "docile/fallback_context_proxy"
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# Docile keeps your Ruby DSLs tame and well-behaved
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# @see http://ms-ati.github.com/docile/
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module Docile
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# Execute a block in the context of an object whose methods represent the
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# commands in a DSL.
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#
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# @note Use with an *imperative* DSL (commands modify the context object)
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#
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# Use this method to execute an *imperative* DSL, which means that:
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#
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# 1. each command mutates the state of the DSL context object
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# 2. the return values of the commands are ignored
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#
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# @example Use a String as a DSL
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# Docile.dsl_eval("Hello, world!") do
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# reverse!
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# upcase!
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# end
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# #=> "!DLROW ,OLLEH"
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#
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# @example Use an Array as a DSL
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# Docile.dsl_eval([]) do
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# push 1
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# push 2
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# pop
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# push 3
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# end
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# #=> [1, 3]
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#
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# @param dsl [Object] context object whose methods make up the DSL
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# @param args [Array] arguments to be passed to the block
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# @yield the block of DSL commands to be executed against the
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# `dsl` context object
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# @return [Object] the `dsl` context object after executing the block
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def dsl_eval(dsl, *args, &block)
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block_context = eval("self", block.binding)
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proxy_context = FallbackContextProxy.new(dsl, block_context)
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begin
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block_context.instance_variables.each do |ivar|
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value_from_block = block_context.instance_variable_get(ivar)
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proxy_context.instance_variable_set(ivar, value_from_block)
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end
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proxy_context.instance_exec(*args, &block)
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ensure
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block_context.instance_variables.each do |ivar|
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value_from_dsl_proxy = proxy_context.instance_variable_get(ivar)
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block_context.instance_variable_set(ivar, value_from_dsl_proxy)
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end
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end
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dsl
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end
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module_function :dsl_eval
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end
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