rabbitmq parser: create erlang syntax lexer

parslet.rb

@@ -0,0 +1,177 @@
+require 'parslet'
+
+class ErlAx < Parslet::Parser
+  root :outermost
+  # only designed for rabbitmq config files for now:
+  rule(:outermost) { filler? >> array.maybe >> dot.maybe }
+
+  rule(:expression) {
+    (tuple | array | binary | string | bool | identifier | float | integer) >> filler?
+  }
+
+  rule(:array) {
+    str('[') >> filler? >> (
+      expression >>
+      (comma >> expression).repeat
+    ).maybe.as(:array) >> str(']') >> filler?
+  }
+
+  rule(:tuple) {
+    str('{') >> filler? >> (
+      expression >> filler? >>
+      (comma >> expression).repeat
+    ).maybe.as(:tuple) >> str('}') >> filler?
+  }
+
+  rule(:filler?) { space.repeat }
+  rule(:space)   { match('\s+') | match["\n"] | comment }
+
+  rule(:comment) { str('%') >> (match["\n\r"].absent? >> any).repeat }
+  rule(:comma) { str(',') >> filler? }
+  rule(:dot) { str('.') >> filler? }
+  rule(:bool) { str('true').as(:bool) | str('false').as(:bool) }
+
+  rule(:identifier) {
+    (match('[a-zA-Z]') >> match('[a-zA-Z0-9_]').repeat).as(:identifier) >> filler?
+  }
+
+  rule(:float) {
+    (
+      integer >> (
+        str('.') >> match('[0-9]').repeat(1) |
+        str('e') >> match('[0-9]').repeat(1)
+      ).as(:e)
+    ).as(:float) >> filler?
+  }
+
+  rule(:integer) {
+    ((str('+') | str('-')).maybe >> match('[0-9]').repeat(1)).as(:integer) >> filler?
+  }
+
+  rule(:string) { stringS | stringD }
+
+  rule(:stringS) {
+    str("'") >> (
+      str('\\') >> any | str("'").absent? >> any
+    ).repeat.as(:string) >> str("'") >> filler?
+  }
+
+  rule(:stringD) {
+    str('"') >> (
+      str('\\') >> any | str('"').absent? >> any
+    ).repeat.as(:string) >> str('"') >> filler?
+  }
+
+  rule(:binary) {
+    str('<<') >> (
+      str('>>').absent? >> any
+    ).repeat.as(:binary) >> str('>>') >> filler?
+  }
+end
+
+
+
+
+require 'minitest/autorun'
+require 'minitest/spec'
+describe ErlAx do
+  def parse(c)
+    ErlAx.new.parse(c)
+  end
+
+  def parsestr(c)
+    parse(c).to_s
+  end
+
+  def parse_file(f)
+    parse(File.read(f))
+  end
+
+  it 'parses an empty rabbit file' do
+    _(parsestr('')).must_equal ''
+  end
+
+  it 'parses a file with a comment' do
+    _(parsestr("%% -*- mode: erlang -*-\n%%\n")).must_equal "%% -*- mode: erlang -*-\n%%\n"
+  end
+
+  it 'parse simple root array' do
+    _(parsestr("[].\n")).must_equal "{:array=>nil}"
+  end
+
+  it 'parses a root array with an int' do
+    _(parsestr('[1].')).must_equal '{:array=>{:integer=>"1"@1}}'
+  end
+
+  it 'parses a root array with a float' do
+    _(parsestr('[1.1].')).must_equal '{:array=>{:float=>{:integer=>"1"@1, :e=>".1"@2}}}'
+  end
+
+  it 'parses a root array with a double quoted string' do
+    _(parsestr('["st\"r"].')).must_equal '{:array=>{:string=>"st\\\\\\"r"@2}}'
+  end
+
+  it 'parses a root array with a single quoted string' do
+    _(parsestr('[\'st\\\'r\'].')).must_equal '{:array=>{:string=>"st\\\\\'r"@2}}'
+  end
+
+  it 'parses a root array with a binary' do
+    _(parsestr('[<<0, G, B>>].')).must_equal '{:array=>{:binary=>"0, G, B"@3}}'
+  end
+
+  it 'parses a root array with a boolean' do
+    _(parsestr('[true].')).must_equal '{:array=>{:bool=>"true"@1}}'
+  end
+
+  it 'parses a root array with an identifier' do
+    _(parsestr('[hello_world123].')).must_equal '{:array=>{:identifier=>"hello_world123"@1}}'
+  end
+
+  it 'parses a root array with multiple elements' do
+    _(parsestr("[1, \"a\" %%\n, true\n\t].")).must_equal '{:array=>[{:integer=>"1"@1}, {:string=>"a"@5}, {:bool=>"true"@13}]}'
+  end
+
+  it 'parses a root array with an tuple' do
+    _(parsestr('[{}].')).must_equal '{:array=>{:tuple=>nil}}'
+  end
+
+  it 'parses a root array with an tuple' do
+    _(parsestr('[{handshake_timeout, 100}].')).must_equal '{:array=>{:tuple=>[{:identifier=>"handshake_timeout"@2}, {:integer=>"100"@21}]}}'
+  end
+
+  it 'parses a root array with a stringy tuple' do
+    _(parsestr('[{ab, [{"c", 1},{"d",2}]}].')).must_equal '{:array=>{:tuple=>[{:identifier=>"ab"@2}, {:array=>[{:tuple=>[{:string=>"c"@9}, {:integer=>"1"@13}]}, {:tuple=>[{:string=>"d"@18}, {:integer=>"2"@21}]}]}]}}'
+  end
+
+  it 'parses a complex deep array-tuple mix' do
+    _(parsestr('[{rabbit,[{two,[]}]}].')).must_equal '{:array=>{:tuple=>[{:identifier=>"rabbit"@2}, {:array=>{:tuple=>[{:identifier=>"two"@11}, {:array=>nil}]}}]}}'
+  end
+
+  it 'parses a complex multi array tuple mix' do
+    _(parsestr('[{rabbit,[{two,[]}]}, 3, false].')).must_equal '{:array=>[{:tuple=>[{:identifier=>"rabbit"@2}, {:array=>{:tuple=>[{:identifier=>"two"@11}, {:array=>nil}]}}]}, {:integer=>"3"@22}, {:bool=>"false"@25}]}'
+  end
+
+  it 'parses a complex array-tuple mix with comments' do
+    s = '%% -*-  mode: erlang -*-
+[
+  {rabbit,
+    [%%
+
+     %% some  more text
+     {tcp_listeners, [5672]}
+   ]}].
+'
+    _(parsestr(s)).must_equal '{:array=>{:tuple=>[{:identifier=>"rabbit"@29}, {:array=>{:tuple=>[{:identifier=>"tcp_listeners"@75}, {:array=>{:integer=>"5672"@91}}]}}]}}'
+  end
+
+  it 'parses a real rabbitmq config file' do
+    f = 'rabbitmq.config'
+    unless File.file?(f)
+      puts "NO #{f}, skipping this check!"
+      return
+    end
+    puts 'Wheeee, testing a real rabbitmq nasty config file'
+    c = File.read(f)
+    parsestr(c)
+  end
+end