lexer: skip #! as a single token at front of line

Fixes #370

core/lexer/lexer.factor

@@ -58,9 +58,23 @@ M: lexer skip-blank ( lexer -- )
 
 GENERIC: skip-word ( lexer -- )
 
+<PRIVATE
+
+: quote? ( column text -- ? )
+    nth CHAR: " eq? ; inline
+
+: shebang? ( column text -- ? )
+    swap zero? [ "#!" head? ] [ drop f ] if ; inline
+
+PRIVATE>
+
 M: lexer skip-word ( lexer -- )
     [
-        2dup nth CHAR: " eq? [ drop 1 + ] [ f skip ] if
+        {
+            { [ 2dup quote? ] [ drop 1 + ] }
+            { [ 2dup shebang? ] [ drop 2 + ] }
+            [ f skip ]
+        } cond
     ] change-lexer-column ;
 
 : still-parsing? ( lexer -- ? )

core/parser/parser-tests.factor

@@ -23,6 +23,12 @@ unit-test
 [ "\"\\n\\r\\t\\\\\"" eval( -- string ) ]
 unit-test
 
+[ "hello world" ]
+[
+"""#!/usr/bin/env factor
+"hello world" """ eval( -- string )
+] unit-test
+
 [ "hello world" ]
 [
     "IN: parser.tests : hello ( -- str ) \"hello world\" ;"