Fix for #277 (incorrect line/col number)

lualib/nelua/thirdparty/lpegrex.lua

@@ -588,18 +588,17 @@ Returns line number, column number, line content, line start position and line e
 ]]
 function lpegrex.calcline(subject, position)
   if position < 0 then error 'invalid position' end
-  local sublen = #subject
-  if position > sublen then position = sublen end
-  local caps = calclinepatt:match(subject:sub(1,position))
-  local ncaps = #caps
-  local lineno = ncaps + 1
-  local lastpos = caps[ncaps] or 0
-  local linestart = lastpos + 1
-  local colno = position - lastpos
-  local lineend = subject:find("\n", position+1, true)
-  lineend = lineend and lineend-1 or #subject
-  local line = subject:sub(linestart, lineend)
-  return lineno, colno, line, linestart, lineend
+  position = math.min(position, #subject)
+  local lastNewlinePatt = lpeg.P {lpeg.Cp() * ((1 - lpeg.P "\n") ^ 0 * "\n") ^ 0 * lpeg.Cp()}
+  local linestart = (lastNewlinePatt:match(subject:sub(1, position)) or 1) - 1
+  local linenum = select(2, subject:sub(1, position):gsub("\n", "\n")) + 1
+  if position > 0 and subject:sub(position, position) == "\n" then
+      linenum = linenum - 1
+  end
+  local lineend = subject:find("\n", position + 1, true) or #subject + 1
+  local line = subject:sub(linestart + 1, lineend - 1)
+  local colnum = position - linestart
+  return linenum, colnum, line, linestart + 1, lineend
 end
 
 -- Auxiliary function for `prettyast`

spec/aster_spec.lua

@@ -2,6 +2,7 @@ local lester = require 'nelua.thirdparty.lester'
 local aster = require 'nelua.aster'
 local expect = require 'spec.tools.expect'
 local Attr = require 'nelua.attr'
+local lpegrex = require 'nelua.thirdparty.lpegrex'
 local describe, it = lester.describe, lester.it
 
 local n = aster
@@ -62,4 +63,12 @@ it("clone", function()
   expect.equal(aster.pretty(aster.clone{n.Id{'x'},n.Number{1}}), aster.pretty{n.Id{'x'},n.Number{1}})
 end)
 
+it("error on line numbers", function()
+  expect.fail(function() 
+    aster.parse([[print(]])
+  end, "unclosed parenthesis, did you forget a `)`?")
+  local lineno, colno = lpegrex.calcline("print(", 6)
+  assert(lineno == 1 and colno == 6, "expected error at line 1, column 6")
+end)
+
 end)