stream: add `read_word` and `read_nonwhitespace`

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

diff --git a/lib/standard/stream.nit b/lib/standard/stream.nit
index 476c684..1e4ba18 100644 (file)
--- a/lib/standard/stream.nit
+++ b/lib/standard/stream.nit
@@ -220,6 +220,66 @@ abstract class Reader
        # Is there something to read.
        # This function returns 'false' if there is something to read.
        fun eof: Bool is abstract
+
+       # Read the next sequence of non whitespace characters.
+       #
+       # Leading whitespace characters are skipped.
+       # The first whitespace character that follows the result is consumed.
+       #
+       # An empty string is returned if the end of the file or an error is encounter.
+       #
+       # ~~~
+       # var w = new StringReader(" Hello, \n\t World!")
+       # assert w.read_word == "Hello,"
+       # assert w.read_char == '\n'.ascii
+       # assert w.read_word == "World!"
+       # assert w.read_word == ""
+       # ~~~
+       #
+       # `Char::is_whitespace` determines what is a whitespace.
+       fun read_word: String
+       do
+               var buf = new FlatBuffer
+               var c = read_nonwhitespace
+               if c > 0 then
+                       buf.add(c.ascii)
+                       while not eof do
+                               c = read_char
+                               if c < 0 then break
+                               var a = c.ascii
+                               if a.is_whitespace then break
+                               buf.add(a)
+                       end
+               end
+               var res = buf.to_s
+               return res
+       end
+
+       # Skip whitespace characters (if any) then return the following non-whitespace character.
+       #
+       # Returns the code point of the character.
+       # Return -1 on end of file or error.
+       #
+       # In fact, this method works like `read_char` except it skips whitespace.
+       #
+       # ~~~
+       # var w = new StringReader(" \nab\tc")
+       # assert w.read_nonwhitespace == 'a'.ascii
+       # assert w.read_nonwhitespace == 'b'.ascii
+       # assert w.read_nonwhitespace == 'c'.ascii
+       # assert w.read_nonwhitespace == -1
+       # ~~~
+       #
+       # `Char::is_whitespace` determines what is a whitespace.
+       fun read_nonwhitespace: Int
+       do
+               var c = -1
+               while not eof do
+                       c = read_char
+                       if c < 0 or not c.ascii.is_whitespace then break
+               end
+               return c
+       end
 end
 
 # Iterator returned by `Reader::each_line`.