I have the following specs
it "parses a document with only an expression" do
puts parser.document.should parse("[b]Hello World[/b]")
end
it "parses a document with only text" do
puts parser.document.should parse(" Hello World")
end
it "parses a document with both an expression and text" do
puts parser.document.should parse("[b]Hello World[/b] Yes hello")
end
For the following Parslet Parser
class Parser < Parslet::Parser
rule(:open_tag) do
parslet = str('[')
parslet = parslet >> (str(']').absent? >> match("[a-zA-Z]")).repeat(1).as(:open_tag_name)
parslet = parslet >> str(']')
parslet
end
rule(:close_tag) do
parslet = str('[/')
parslet = parslet >> (str(']').absent? >> match("[a-zA-Z]")).repeat(1).as(:close_tag_name)
parslet = parslet >> str(']')
parslet
end
rule(:text) { any.repeat(1).as(:text) }
rule(:expression) do
# [b]Hello World[/b]
# open tag, any text up until closing tag, closing tag
open_tag.present?
close_tag.present?
parslet = open_tag >> match("[a-zA-Z\s?]").repeat(1).as(:enclosed_text) >> close_tag
parslet
end
rule(:document) do
expression | text
end
The first two tests pass just fine, and I can see by puting them out to the command line that the atoms are of the correct type. However, when I try to parse a document with both an expression and plain text, it fails to parse the plain text, failing with the following error
Parslet::UnconsumedInput: Don't know what to do with " Yes hello" at line 1 char 19.
I think I'm missing something regarding defining the :document rule. What I want is something that will consume any number of in sequence expressions and plain text, and while the rule I have will consume each atom individual, using them both in the same string causes failure.
For your document rule you want to use repeat:
rule(:document) do
(expression | text).repeat
end
You’ll also need to change your text rule; currently if it starts matching it will consume everything including any [ that should start a new expression. Something like this should work:
rule(:text) { match['^\['].repeat(1).as(:text) }