Proto: meaning etc.

nellie/interpreter.lua

@@ -1,59 +1,6 @@
-require("helper")
+require("nellie.helper")
 
 -- CLASS DEFINITIONS
--- A stream of text (kind of)
--- with some helping methods
-Reader = class("Reader")
--- Construct a reader from
-function Reader:new(text)
-  assert_type("string")(text,"Arg 'text' #1: %s")
-  self.text = text
-end
--- Get the substring of the readers text in a bounds
-function Reader:get(first,final)
-  assert_type("number")(first,"Arg 'first' #1: %s")
-  assert_type("number","nil")(final,"Arg 'final' #2: %s")
-  return self.text:sub(first,final)
-end
--- Match on the reader's text from an index
-function Reader:find(pattern,init)
-  assert_type("string")(pattern,"Arg 'pattern' #1: %s")
-  assert_type("number","nil")(init,"Arg 'init' #2: %s")
-  return self.text:find(pattern,init)
-end
-function Reader:match(pattern,init)
-  assert_type("string")(pattern,"Arg 'pattern' #1: %s")
-  assert_type("number")(init,"Arg 'init' #2: %s")
-  return self.text:match(pattern,init)
-end
-
--- A range of text being considered
--- like a cursor
-Range = class("Range")
--- Construct a range of text from a reader and bounds
-function Range:new(reader,first,final)
-  assert_meta(Reader)(reader)
-  assert_type("number","nil")(first,"Arg 'first' #1: %s")
-  assert_type("number","nil")(final,"Arg 'final' #2: %s")
-  self.reader = reader
-  self.first = first
-  self.final = final
-end
-function Range:text()
-  return self.reader:get(self.first or 1,self.final)
-end
-function Range:find(pattern)
-  return self.reader:find(pattern,self.first)
-end
-function Range:move(first,final)
-  assert_type("number","nil")(first,"Arg 'first' #1: %s")
-  assert_type("number","nil")(final,"Arg 'final' #2: %s")
-  self.first = first
-  self.final = final
-  -- note that this function returns itself
-  return self
-end
-
 Expression = class("Expression")
 -- Construct an expression from items (or not)
 function Expression:new(items)
@@ -191,76 +138,6 @@ function Expression:link(msg)
   )
 end
 
---[[
-A class which parses text using the 'consumer-meal'
-model.
-]]
-Consumer = class("Consumer")
-function Consumer:new(content)
-  self.range = Range(Reader(content))
-  self.col = 1
-  self.row = 1
-end
-function Consumer:remaining()
-  return self.range:text()
-end
-function Consumer:mark()
-
-end
--- From a table of actions of patterns,
--- consume the earliest pattern (index)
--- and call the value
-function Consumer:consume(t)
-  -- t: {string = function...}
-  assert_type("table")(t,"Arg 't' #1: %s")
-  if not next(t) then 
-    error("The match table cannot be empty!",2)
-  end
-  for index,func in pairs(t) do
-    assert_type("string")(index,"Bad 't' index: %s")
-    assert_type("function")(func,"Bad 't' item: %s")
-  end
-  local origin = self.range.first or 1
-  -- Get the next earliest match
-  local findex,ffinal,fpattern,ffunc,fexcess
-  for pattern,new_func in pairs(t) do
-    local new_index,new_final = self.range:find(pattern)
-    if new_index and 
-      ((not findex) or (findex > new_index))
-    then
-      if not new_index then return end
-      findex = new_index
-      ffinal = new_final
-      fpattern = pattern
-      ffunc = new_func
-      fexcess = self.range.reader:get(
-        self.range.first or 1,
-        new_final - 1
-      )
-    end
-  end
-  -- Pass into the func
-  if not ffunc then 
-    return nil
-  end
-  assert(findex) assert(ffinal)
-  self.range:move(ffinal+1) -- Move range to after the match
-  local fmatch = self.range.reader:match(fpattern,findex)
-  -- Pass back consumed result to
-  local sum = self.range.reader:get(origin+1,self.range.first)
-    :gsub("\r\n","\n")
-    :gsub("\r","\n")
-  for char in sum:gmatch(".") do
-    if char == "\n" then 
-      self.row = self.row + 1
-      self.col = 1
-    else
-      self.col = self.col + 1
-    end
-  end
-  return ffunc(fexcess,fmatch)
-end
-
 Binding = class("Binding")
 -- Construct from a neli string to infer a binding
 -- note that you must wrap this definition in "(<def>)"!
@@ -362,6 +239,7 @@ function Chain:pcall(func)
   local success,result = xpcall(func,function(msg)
     -- If this is a 'nel:' error, strip the line responsible
     -- Otherwise just return the whole traceback since something went really bad
+    if not msg then msg = "no message provided" end
     local match = msg:match("nel:%s(.*)")
     if match then
       return match
@@ -400,7 +278,13 @@ function Scope:insert(binding)
   assert_meta(Binding)(binding,"Arg 'binding' #1: %s")
   for competitor in iterate(self.bindings) do
     if competitor:check(binding.template) then
-      error(string.format("nel: Conflicting sibling bindings in scope for '%s'.",binding.template))
+      error(
+        string.format(
+          "nel: Conflicting sibling binding in scope for '%s': '%s'.",
+          binding.template,
+          competitor.template
+        )
+      )
     end
   end
   table.insert(self.bindings,binding)