initial release

cosmic rage/lua/getstyle.lua

@@ -0,0 +1,49 @@
+-- getstyle.lua
+--
+
+--[[
+
+See forum thread:  http://www.gammon.com.au/forum/?id=7818
+
+GetStyle:
+  Finds a style run corresponding to a given column 
+
+  Returns nil if style run not found (eg. column out of range)
+
+  If style run found returns: 
+     * the style table (see below)
+     * the character at that column
+     * the style run number (eg. style 3)
+
+The style table should contain the following:
+
+  t.text        --> text of that (entire) style run
+  t.length      --> length of the (entire) style run
+  t.textcolour  --> text colour (RGB number)
+  t.backcolour  --> background colour (RGB number)
+  t.style       --> style bits (1=bold, 2=underline, 4=italic)
+
+--]]
+
+function GetStyle (styleRuns, wantedColumn)
+local currentColumn = 1
+
+   -- check arguments
+   assert (type (styleRuns) == "table", 
+           "First argument to GetStyle must be table of style runs")
+
+   assert (type (wantedColumn) == "number" and wantedColumn >= 1, 
+           "Second argument to GetStyle must be column number to find")
+
+   -- go through each style
+   for item, style in ipairs (styleRuns) do
+     local position = wantedColumn - currentColumn + 1  -- where letter is in style
+     currentColumn = currentColumn + style.length       -- next style starts here
+     if currentColumn > wantedColumn then  -- if we are within this style
+        return style, string.sub (style.text, position, position), item  -- done
+     end -- if found column
+   end -- for each style
+
+   -- if not found: result is nil
+
+end -- function GetStyle