lib/standard/string: Added function to format a String using a new notation

[nit.git] / lib / standard / string.nit

diff --git a/lib/standard/string.nit b/lib/standard/string.nit
index cd2698c..5c9b2ef 100644 (file)
--- a/lib/standard/string.nit
+++ b/lib/standard/string.nit
@@ -849,6 +849,39 @@ abstract class Text
                return hash_cache.as(not null)
        end
 
+       # Gives the formatted string back as a Nit string with `args` in place
+       #
+       #       assert "This %1 is a %2.".format("String", "formatted String") == "This String is a formatted String"
+       #       assert "\\%1 This string".format("String") == "\\%1 This string"
+       fun format(args: Object...): String do
+               var s = new Array[Text]
+               var curr_st = 0
+               var i = 0
+               while i < length do
+                       # Skip escaped characters
+                       if self[i] == '\\' then
+                               i += 1
+                       # In case of format
+                       else if self[i] == '%' then
+                               var fmt_st = i
+                               i += 1
+                               var ciph_st = i
+                               while i < length and self[i].is_numeric do
+                                       i += 1
+                               end
+                               i -= 1
+                               var fmt_end = i
+                               var ciph_len = fmt_end - ciph_st + 1
+                               s.push substring(curr_st, fmt_st - curr_st)
+                               s.push args[substring(ciph_st, ciph_len).to_i - 1].to_s
+                               curr_st = i + 1
+                       end
+                       i += 1
+               end
+               s.push substring(curr_st, length - curr_st)
+               return s.to_s
+       end
+
 end
 
 # All kinds of array-based text representations.