to clarify.. something like this...
rule(:magic_label) { magic_words.inject(false){ |result,element| result =
result | "magic_#{ element }".to_sym }
I think the 'false' should really be an instance of
Parslet::Atom::Base::Fail
---
"No man is an island... except Philip"
On 22 February 2012 11:09, Nigel Thorne <[email protected]> wrote:
> You want to use 'inject' or 'reduce' not map.
>
> You are building up a matcher by 'or'ing it with the previous matcher.
>
>
> ---
> "No man is an island... except Philip"
>
>
>
> On 22 February 2012 04:16, David Sklar <[email protected]> wrote:
>
>> I have a list of strings that are magical tokens in the pre-existing
>> language I am writing a grammar for.
>>
>> Right now, my rules for parsing them look something like:
>>
>>
>> rule(:regular_label) { match('[a-z0-9.]').repeat(1) }
>>
>> magic_words = ["magic1","moremagic","evenmoremagic"]
>>
>> magic_words.each do |m|
>> rule("magic_{#m}".to_sym) { str(m) }
>> end
>>
>> rule(:magic_label) { :magic_magic1 | :magic_moremagic |
>> :magic_evenmoremagic }
>>
>>
>> rule(:any_label) { :magic_label | :regular_label }
>>
>> Is there a way I can dynamically generate the :magic_label rule? I'd
>> like to avoid having to update two places if the list of magic strings
>> changes.
>>
>> I.e. in pseudocode, I'd like to be able to do something like:
>>
>> rule(:magic_label) {
>> something_wonderful(magic_words.map |m| { "magic_#{m}.to_sym" }.join('
>> | '))
>> }
>>
>> Where the something_wonderful() method would take the string it is
>> passed and turn it into a rule body.
>>
>> Thanks,
>> David
>>
>>
>
