py/lexer: Simplify handling of line-continuation error.

dpgeorge · dpgeorge · commit 773278ec3030 · 2017-02-17T11:30:14.000+11:00
Previous to this patch there was an explicit check for errors with line
continuation (where backslash was not immediately followed by a newline).

But this check is not necessary: if there is an error then the remaining
logic of the tokeniser will reject the backslash and correctly produce a
syntax error.
diff --git a/py/lexer.c b/py/lexer.c
@@ -290,18 +290,10 @@ void mp_lexer_to_next(mp_lexer_t *lex) {
                 next_char(lex);
             }
             // had_physical_newline will be set on next loop
-        } else if (is_char(lex, '\\')) {
-            // backslash (outside string literals) must appear just before a physical newline
+        } else if (is_char_and(lex, '\\', '\n')) {
+            // line-continuation, so don't set had_physical_newline
+            next_char(lex);
             next_char(lex);
-            if (!is_physical_newline(lex)) {
-                // SyntaxError: unexpected character after line continuation character
-                lex->tok_line = lex->line;
-                lex->tok_column = lex->column;
-                lex->tok_kind = MP_TOKEN_BAD_LINE_CONTINUATION;
-                return;
-            } else {
-                next_char(lex);
-            }
         } else {
             break;
         }
diff --git a/py/lexer.h b/py/lexer.h
@@ -39,26 +39,25 @@
  */
 
 typedef enum _mp_token_kind_t {
-    MP_TOKEN_END,                   // 0
+    MP_TOKEN_END,
 
     MP_TOKEN_INVALID,
     MP_TOKEN_DEDENT_MISMATCH,
     MP_TOKEN_LONELY_STRING_OPEN,
-    MP_TOKEN_BAD_LINE_CONTINUATION,
 
-    MP_TOKEN_NEWLINE,               // 5
-    MP_TOKEN_INDENT,                // 6
-    MP_TOKEN_DEDENT,                // 7
+    MP_TOKEN_NEWLINE,
+    MP_TOKEN_INDENT,
+    MP_TOKEN_DEDENT,
 
-    MP_TOKEN_NAME,                  // 8
+    MP_TOKEN_NAME,
     MP_TOKEN_INTEGER,
     MP_TOKEN_FLOAT_OR_IMAG,
     MP_TOKEN_STRING,
     MP_TOKEN_BYTES,
 
     MP_TOKEN_ELLIPSIS,
 
-    MP_TOKEN_KW_FALSE,              // 14
+    MP_TOKEN_KW_FALSE,
     MP_TOKEN_KW_NONE,
     MP_TOKEN_KW_TRUE,
     MP_TOKEN_KW___DEBUG__,
