nitc: add Location::get_line

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/location.nit b/src/location.nit
index 99083ad..36157d3 100644 (file)
--- a/src/location.nit
+++ b/src/location.nit
@@ -47,6 +47,20 @@ class SourceFile
        #
        # Used for fast access to each line when rendering parts of the `string`.
        var line_starts = new Array[Int]
+
+       # Extract a given line excluding the line-terminators characters.
+       #
+       # `line_number` starts at 1 for the first line.
+       fun get_line(line_number: Int): String do
+               if line_number > line_starts.length then return ""
+               var line_start = line_starts[line_number-1]
+               var line_end = line_start
+               var string = self.string
+               while line_end+1 < string.length and string.chars[line_end+1] != '\n' and string.chars[line_end+1] != '\r' do
+                       line_end += 1
+               end
+               return string.substring(line_start, line_end-line_start+1)
+       end
 end
 
 # A location inside a source file