Improvement: expose cecho2ansi and have it work for non-ansi color na…

…mes as well (#5672)

#### Brief overview of PR changes/additions
While perusing the ansi conversion functions I realized we were doing all the work of cecho2ansi but had not exposed it as separate functionality. Since we have done so for d and hecho, it made sense to me to perform this refactor.
In the process I also added support for colors which are not named ansi colors but exist in the color table. 
#### Motivation for adding to Mudlet
More complete API, consistency across the c/d/h variants.

src/mudlet-lua/lua/GUIUtils.lua

@@ -1485,12 +1485,20 @@ if rex then
         local colorNumber = ctable[fore]
         if colorNumber then
           result = string.format("%s\27[38:5:%sm", result, colorNumber)
+        elseif color_table[fore] then
+          local rgb = color_table[fore]
+          result = string.format("%s\27[38:2::%s:%s:%sm", result, rgb[1], rgb[2], rgb[3])
         end
       end
     end
     if back then
       local colorNumber = ctable[back]
-      result = string.format("%s\27[48:5:%sm", result, colorNumber)
+      if colorNumber then
+        result = string.format("%s\27[48:5:%sm", result, colorNumber)
+      elseif color_table[back] then
+        local rgb = color_table[back]
+        result = string.format("%s\27[48:2::%s:%s:%sm", result, rgb[1], rgb[2], rgb[3])
+      end
     end
     return result
   end
@@ -1537,6 +1545,18 @@ if rex then
     return result
   end
 
+  function cecho2ansi(text)
+    local colorPattern = _Echos.Patterns.Color[1]
+    local result = ""
+    for str, color in rex.split(text, colorPattern) do
+      result = result .. str
+      if color then
+        result = result .. colorToAnsi(color:match("<(.+)>"))
+      end
+    end
+    return result
+  end
+
   --- feedTriggers with cecho style color information.
   -- Valid colors are  black,red,green,yellow,blue,magenta,cyan,white and light_* versions of same
   -- Can also pass in a number between 0 and 255 to use the expanded ansi 255 colors. IE <124> will set foreground to the color ANSI124
@@ -1546,15 +1566,7 @@ if rex then
   --@see cecho
   --@see cinsertText
   function cfeedTriggers(text)
-    local colorPattern = _Echos.Patterns.Color[1]
-    local result = ""
-    for str, color in rex.split(text, colorPattern) do
-      result = result .. str
-      if color then
-        result = result .. colorToAnsi(color:match("<(.+)>"))
-      end
-    end
-    feedTriggers(result .. "\n")
+    feedTriggers(cecho2ansi(text) .. "\n")
     echo("")
   end
 

src/mudlet-lua/tests/GUIUtils_spec.lua

@@ -198,6 +198,45 @@ describe("Tests the GUI utilities as far as possible without mudlet", function()
     end)
   end)
 
+  describe("Tests the functionality of cecho2ansi()", function()
+    local simple_original = "<red>This is in red<r> And then reset."
+    local simple_expected = "\27[38:5:1mThis is in red\27[0m And then reset."
+
+    it("should convert a simple cecho string to an equivalent ansi string", function()
+      local actual = cecho2ansi(simple_original)
+      assert.equals(simple_expected, actual)
+    end)
+
+    it("should convert a color name which doesn't have a direct ansi named equivalent", function()
+      local actual = cecho2ansi("<DodgerBlue>")
+      assert.equals("\27[38:2::30:144:255m", actual)
+    end)
+
+    it("should handle bold", function()
+      local expected = "\27[1mbold\27[22m"
+      local actual = cecho2ansi("<b>bold</b>")
+      assert.equals(expected, actual)
+    end)
+
+    it("should handle underline", function()
+      local expected = "\27[4munderline\27[24m"
+      local actual = cecho2ansi("<u>underline</u>")
+      assert.equals(expected, actual)
+    end)
+
+    it("should handle italics", function()
+      local expected = "\27[3mitalics\27[23m"
+      local actual = cecho2ansi("<i>italics</i>")
+      assert.equals(expected, actual)
+    end)
+
+    it("should handle strikeout", function()
+      local expected = "\27[9mstrikeout\27[29m"
+      local actual = cecho2ansi("<s>strikeout</s>")
+      assert.equals(expected, actual)
+    end)
+  end)
+
   describe("Tests the functionality of ansi2string()", function()
     it("should return the string fed into it with ansi codes removed", function()
       local original = '\27[38;5;179;48;5;230mYou say in a baritone voice, "Test."\27[0;37;40m'