some docs

lib/parser/composed.rb

@@ -12,6 +12,11 @@ module Parser
     include Tokens
     include Keywords
     
+    # Note about the lists (argument and parameter)
+    # Beause of the maybe for the comma ...  part , the rules may return either 
+    # - a single simple version with one element 
+    # a sequence with many element. 
+    # This leads to the fact that two transform rules are needed for either 
     rule(:argument_list) {
       left_parenthesis >>
       ((expression.as(:argument) >> (comma >> expression.as(:argument)).repeat(0)).maybe).as(:argument_list) >>

lib/parser/transform.rb

@@ -9,6 +9,7 @@ module Parser
     rule(:argument  => simple(:argument))    { argument  }
     rule(:argument_list => sequence(:argument_list)) { argument_list }
 
+    # need TWO transform rules, for one/many arguments (see the[] wrapping in the first)
     rule(:function_call => simple(:function_call),
           :argument_list    => simple(:argument))   do
             Vm::FuncallExpression.new(function_call.name, [argument]) 
@@ -25,6 +26,7 @@ module Parser
     rule(:parmeter  => simple(:parmeter))    { parmeter  }
     rule(:parmeter_list => sequence(:parmeter_list)) { parmeter_list }
 
+    # need TWO transform rules, for one/many arguments (see the[] wrapping in the first)
     rule(:function_definition   => simple(:function_definition),
          :parmeter_list => simple(:parmeter),
          :block   => simple(:block)) do