Updating the documentation and the examples

1 files changed, 31 insertions, 18 deletions

diff --git a/examples/listIdRe2.lua b/examples/listIdRe2.lua
index 4cd140b..ccb7ce5 100644
--- a/examples/listIdRe2.lua
+++ b/examples/listIdRe2.lua
@@ -1,35 +1,48 @@
 local re = require 'relabel' 
 
-local errUndef, errId, errComma = 0, 1, 2
-
-local terror = {
-        [errUndef] = "Error",
-        [errId] = "Error: expecting an identifier",
-        [errComma] = "Error: expecting ','",
+local errinfo = {
+        {"errUndef",  "undefined"},
+        {"errId",     "expecting an identifier"},
+        {"errComma",  "expecting ','"},
 }
 
-local tlabels = { ["errUndef"] = errUndef,
-                  ["errId"]    = errId, 
-                  ["errComma"] = errComma }
+local errmsgs = {}
+local labels = {}
+
+for i, err in ipairs(errinfo) do
+  errmsgs[i] = err[2]
+  labels[err[1]] = i
+end
+
+re.setlabels(labels)
+
+local function calcline (s, i)
+  if i == 1 then return 1, 1 end
+  local rest, line = s:sub(1,i):gsub("[^\n]*\n", "")
+  local col = #rest
+  return 1 + line, col ~= 0 and col or 1
+end
 
-re.setlabels(tlabels)
 
 local g = re.compile[[
-  S    <- Id List
-  List <- !.  /  (',' /         %{errComma}) Id List
-  Id   <- [a-z]  /  %{errId}    
+  S      <- Id List
+  List   <- !.  /  (',' /       %{errComma}) (Id / %{errId}) List
+  Id     <- Sp [a-z]+
+  Comma  <- Sp ','
+  Sp     <- %s*
 ]]
 
 function mymatch (g, s)
         local r, e, sfail = g:match(s)
         if not r then
-                return r, terror[e] .. " before '" .. sfail .. "'"
+                local line, col = calcline(s, #s - #sfail)
+                local msg = "Error at line " .. line .. " (col " .. col .. "): "
+                return r, msg .. errmsgs[e] .. " before '" .. sfail .. "'"
         end
         return r
 end
-        
-print(mymatch(g, "a,b"))
-print(mymatch(g, "a b"))
-print(mymatch(g, ", b"))
 
+print(mymatch(g, "one,two"))
+print(mymatch(g, "one two"))
+print(mymatch(g, "one,\n two,\nthree,"))