X-Git-Url: http://nitlanguage.org

diff --git a/src/location.nit b/src/location.nit
index 0603050..c092b28 100644
--- a/src/location.nit
+++ b/src/location.nit
@@ -15,7 +15,7 @@
 # limitations under the License.
 
 # This module is used to model Nit source-file and locations in source-file
-package location
+module location
 
 # A raw text Nit source file
 class SourceFile
@@ -33,8 +33,16 @@ class SourceFile
 		line_starts[0] = 0
 	end
 
+	# Create a new sourcefile using a dummy filename and a given content
+	init from_string(filename: String, string: String)
+	do
+		self.filename = filename
+		self.string = string
+		line_starts[0] = 0
+	end
+
 	# Position of each line start
-	var line_starts: Array[Int] = new Array[Int]
+	var line_starts = new Array[Int]
 end
 
 # A location inside a source file
@@ -42,20 +50,41 @@ class Location
 	super Comparable
 	redef type OTHER: Location
 
-	readable var _file: nullable SourceFile
-	readable var _line_start: Int
-	readable var _line_end: Int
-	readable var _column_start: Int
-	readable var _column_end: Int
+	var file: nullable SourceFile
+	var line_start: Int
+	var line_end: Int
+	var column_start: Int
+	var column_end: Int
 
 	init(f: nullable SourceFile, line_s: Int, line_e: Int, column_s: Int, column_e: Int) do
-		_file = f
-		_line_start = line_s
-		_line_end = line_e
-		_column_start = column_s
-		_column_end = column_e
+		file = f
+		line_start = line_s
+		line_end = line_e
+		column_start = column_s
+		column_end = column_e
+	end
+
+	# The index in the start character in the source
+	fun pstart: Int do return file.line_starts[line_start-1] + column_start-1
+
+	# The index on the end character in the source
+	fun pend: Int do return file.line_starts[line_end-1] + column_end-1
+
+	# The verbatim associated text in the source-file
+	fun text: String
+	do
+		var res = self.text_cache
+		if res != null then return res
+		var l = self
+		var pstart = self.pstart
+		var pend = self.pend
+		res = l.file.string.substring(pstart, pend-pstart+1)
+		self.text_cache = res
+		return res
 	end
 
+	private var text_cache: nullable String
+
 	init with_file(f: SourceFile) do init(f,0,0,0,0)
 
 	redef fun ==(other: nullable Object): Bool do
@@ -71,6 +100,7 @@ class Location
 		return true
 	end
 
+	# Is `self` included (or equals) to `loc`?
 	fun located_in(loc: nullable Location): Bool do
 		if loc == null then return false
 
@@ -107,6 +137,9 @@ class Location
 		end
 	end
 
+	# Return a location message according to an observer.
+	#
+	# Currently, if both are in the same file, the file information is not present in the result.
 	fun relative_to(loc: nullable Location): String do
 		var relative: Location
 		if loc != null and loc.file == self.file then
@@ -128,5 +161,50 @@ class Location
 
 		return column_end < other.column_end
 	end
-end
 
+	# Return the associated line with the location highlighted with color and a caret under the starting position
+	# `color` must be and terminal escape sequence used as `"{escape}[{color}m;"`
+	# * `"0;31"` for red
+	# * `"1;31"` for bright red
+	# * `"0;32"` for green
+	fun colored_line(color: String): String
+	do
+		var esc = 27.ascii
+		var def = "{esc}[0m"
+		var col = "{esc}[{color}m"
+
+		var l = self
+		var i = l.line_start
+		var line_start = l.file.line_starts[i-1]
+		var line_end = line_start
+		var string = l.file.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
+		var lstart = string.substring(line_start, l.column_start - 1)
+		var cend
+		if i != l.line_end then
+			cend = line_end - line_start + 1
+		else
+			cend = l.column_end
+		end
+		var lmid
+		var lend
+		if line_start + cend <= string.length then
+			lmid = string.substring(line_start + l.column_start - 1, cend - l.column_start + 1)
+			lend = string.substring(line_start + cend, line_end - line_start - cend + 1)
+		else
+			lmid = ""
+			lend = ""
+		end
+		var indent = new FlatBuffer
+		for j in [line_start..line_start+l.column_start-1[ do
+			if string.chars[j] == '\t' then
+				indent.add '\t'
+			else
+				indent.add ' '
+			end
+		end
+		return "\t{lstart}{col}{lmid}{def}{lend}\n\t{indent}^"
+	end
+end