segment: Add support for segmenting "snippets".

[pspp] / src / language / lexer / scan.c

diff --git a/src/language/lexer/scan.c b/src/language/lexer/scan.c
index de75eeef3bd1f519a5508c55924be76cc6a2bd66..57e3c2d1a871cc13c4970a1b349449db12cea68e 100644 (file)
--- a/src/language/lexer/scan.c
+++ b/src/language/lexer/scan.c
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2010, 2011 Free Software Foundation, Inc.
+   Copyright (C) 2010, 2011, 2013 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -324,6 +324,7 @@ scan_punct1__ (char c0)
     case '<': return T_LT;
     case '>': return T_GT;
     case '~': return T_NOT;
+    default: return T_MACRO_PUNCT;
     }
 
   NOT_REACHED ();
@@ -410,7 +411,7 @@ scan_type_to_string (enum scan_type type)
 #undef SCAN_TYPE
 
     default:
-      return token_type_to_name (type);
+      return token_type_to_name ((enum token_type) type);
     }
 }
 
@@ -440,6 +441,7 @@ scan_start__ (struct scanner *scanner, enum segment_type type,
     case SEG_DO_REPEAT_COMMAND:
     case SEG_INLINE_DATA:
     case SEG_DOCUMENT:
+    case SEG_MACRO_BODY:
       token->type = T_STRING;
       ss_alloc_substring (&token->string, s);
       return SCAN_DONE;
@@ -453,6 +455,11 @@ scan_start__ (struct scanner *scanner, enum segment_type type,
       ss_alloc_substring (&token->string, s);
       return SCAN_DONE;
 
+    case SEG_MACRO_ID:
+      token->type = T_MACRO_ID;
+      ss_alloc_substring (&token->string, s);
+      return SCAN_DONE;
+
     case SEG_PUNCT:
       if (s.length == 1 && s.string[0] == '-')
         {
@@ -462,6 +469,8 @@ scan_start__ (struct scanner *scanner, enum segment_type type,
       else
         {
           token->type = scan_punct__ (s);
+          if (token->type == T_MACRO_PUNCT)
+            ss_alloc_substring (&token->string, s);
           return SCAN_DONE;
         }
 
@@ -497,15 +506,8 @@ scan_start__ (struct scanner *scanner, enum segment_type type,
       ss_alloc_substring (&token->string, s);
       return SCAN_DONE;
 
-    case SEG_UNEXPECTED_DOT:
-      token->type = SCAN_UNEXPECTED_DOT;
-      return SCAN_DONE;
-
     case SEG_UNEXPECTED_CHAR:
       return scan_unexpected_char (&s, token);
-
-    case SEG_N_TYPES:
-      NOT_REACHED ();
     }
 
   NOT_REACHED ();
@@ -546,7 +548,7 @@ void
 scanner_init (struct scanner *scanner, struct token *token)
 {
   scanner->state = S_START;
-  token_init (token);
+  *token = (struct token) { .type = T_STOP };
 }
 
 /* Adds the segment with type TYPE and UTF-8 text S to SCANNER.  TOKEN must be
@@ -595,3 +597,61 @@ scanner_push (struct scanner *scanner, enum segment_type type,
 
   NOT_REACHED ();
 }
+\f
+/* Initializes SLEX for parsing INPUT, which is LENGTH bytes long, in the
+   specified MODE.
+
+   SLEX has no internal state to free, but it retains a reference to INPUT, so
+   INPUT must not be modified or freed while SLEX is still in use. */
+void
+string_lexer_init (struct string_lexer *slex, const char *input, size_t length,
+                   enum segmenter_mode mode)
+{
+  *slex = (struct string_lexer) {
+    .input = input,
+    .length = length,
+    .offset = 0,
+    .segmenter = segmenter_init (mode, true),
+  };
+}
+
+/*  */
+bool
+string_lexer_next (struct string_lexer *slex, struct token *token)
+{
+  struct segmenter saved_segmenter;
+  size_t saved_offset = 0;
+
+  struct scanner scanner;
+
+  scanner_init (&scanner, token);
+  for (;;)
+    {
+      const char *s = slex->input + slex->offset;
+      size_t left = slex->length - slex->offset;
+      enum segment_type type;
+      int n;
+
+      n = segmenter_push (&slex->segmenter, s, left, true, &type);
+      assert (n >= 0);
+
+      slex->offset += n;
+      switch (scanner_push (&scanner, type, ss_buffer (s, n), token))
+        {
+        case SCAN_BACK:
+          slex->segmenter = saved_segmenter;
+          slex->offset = saved_offset;
+          /* Fall through. */
+        case SCAN_DONE:
+          return token->type != T_STOP;
+
+        case SCAN_MORE:
+          break;
+
+        case SCAN_SAVE:
+          saved_segmenter = slex->segmenter;
+          saved_offset = slex->offset;
+          break;
+        }
+    }
+}