X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Flanguage%2Flexer%2Flexer.c;h=35a9afa381f038968fafb27c05a87d57e408b176;hb=23265697ad1bf77242d28c2ab7a5983a264f6aa4;hp=329003406bf0281b0d01f99db81372bd4b5649b0;hpb=510cc9dd9baf3108ba55cfb7893384517c9930b4;p=pspp

diff --git a/src/language/lexer/lexer.c b/src/language/lexer/lexer.c
index 329003406b..35a9afa381 100644
--- a/src/language/lexer/lexer.c
+++ b/src/language/lexer/lexer.c
@@ -85,6 +85,9 @@ static struct msg_point lex_token_start_point (const struct lex_source *,
 static struct msg_point lex_token_end_point (const struct lex_source *,
                                              const struct lex_token *);
 
+static bool lex_ofs_at_phrase__ (struct lexer *, int ofs, const char *s,
+                                 size_t *n_matchedp);
+
 /* Source offset of the last byte in TOKEN. */
 static size_t
 lex_token_end (const struct lex_token *token)
@@ -282,17 +285,18 @@ struct lexer
   };
 
 static struct lex_source *lex_source__ (const struct lexer *);
-static char *lex_source_get_syntax__ (const struct lex_source *,
-                                      int n0, int n1);
+static char *lex_source_syntax__ (const struct lex_source *,
+                                  int ofs0, int ofs1);
 static const struct lex_token *lex_next__ (const struct lexer *, int n);
 static void lex_source_push_endcmd__ (struct lex_source *);
 static void lex_source_push_parse (struct lex_source *, struct lex_token *);
 static void lex_source_clear_parse (struct lex_source *);
 
 static bool lex_source_get_parse (struct lex_source *);
-static void lex_source_error_valist (struct lex_source *, int n0, int n1,
-                                     const char *format, va_list)
-   PRINTF_FORMAT (4, 0);
+static void lex_source_msg_valist (struct lex_source *, enum msg_class,
+                                   int ofs0, int ofs1,
+                                   const char *format, va_list)
+   PRINTF_FORMAT (5, 0);
 static const struct lex_token *lex_source_next__ (const struct lex_source *,
                                                   int n);
 
@@ -425,27 +429,77 @@ lex_error (struct lexer *lexer, const char *format, ...)
   va_list args;
 
   va_start (args, format);
-  lex_next_error_valist (lexer, 0, 0, format, args);
+  lex_ofs_msg_valist (lexer, SE, lex_ofs (lexer), lex_ofs (lexer),
+                      format, args);
   va_end (args);
 }
 
-/* Prints a syntax error message containing the current token and
-   given message MESSAGE (if non-null). */
+/* Prints a syntax error message for the span of tokens N0 through N1,
+   inclusive, from the current token in LEXER, adding message MESSAGE (if
+   non-null). */
 void
-lex_error_valist (struct lexer *lexer, const char *format, va_list args)
+lex_next_error (struct lexer *lexer, int n0, int n1, const char *format, ...)
 {
-  lex_next_error_valist (lexer, 0, 0, format, args);
+  va_list args;
+
+  va_start (args, format);
+  int ofs = lex_ofs (lexer);
+  lex_ofs_msg_valist (lexer, SE, n0 + ofs, n1 + ofs, format, args);
+  va_end (args);
 }
 
-/* Prints a syntax error message containing the current token and
-   given message MESSAGE (if non-null). */
+/* Prints a syntax error message for the span of tokens with offsets OFS0
+   through OFS1, inclusive, within the current command in LEXER, adding message
+   MESSAGE (if non-null). */
 void
-lex_next_error (struct lexer *lexer, int n0, int n1, const char *format, ...)
+lex_ofs_error (struct lexer *lexer, int ofs0, int ofs1, const char *format, ...)
+{
+  va_list args;
+
+  va_start (args, format);
+  lex_ofs_msg_valist (lexer, SE, ofs0, ofs1, format, args);
+  va_end (args);
+}
+
+/* Prints a message of the given CLASS containing the current token and given
+   message MESSAGE (if non-null). */
+void
+lex_msg (struct lexer *lexer, enum msg_class class, const char *format, ...)
+{
+  va_list args;
+
+  va_start (args, format);
+  lex_ofs_msg_valist (lexer, class, lex_ofs (lexer), lex_ofs (lexer),
+                      format, args);
+  va_end (args);
+}
+
+/* Prints a syntax error message for the span of tokens N0 through N1,
+   inclusive, from the current token in LEXER, adding message MESSAGE (if
+   non-null). */
+void
+lex_next_msg (struct lexer *lexer, enum msg_class class, int n0, int n1,
+              const char *format, ...)
+{
+  va_list args;
+
+  va_start (args, format);
+  int ofs = lex_ofs (lexer);
+  lex_ofs_msg_valist (lexer, class, n0 + ofs, n1 + ofs, format, args);
+  va_end (args);
+}
+
+/* Prints a message of the given CLASS for the span of tokens with offsets OFS0
+   through OFS1, inclusive, within the current command in LEXER, adding message
+   MESSAGE (if non-null). */
+void
+lex_ofs_msg (struct lexer *lexer, enum msg_class class, int ofs0, int ofs1,
+             const char *format, ...)
 {
   va_list args;
 
   va_start (args, format);
-  lex_next_error_valist (lexer, n0, n1, format, args);
+  lex_ofs_msg_valist (lexer, class, ofs0, ofs1, format, args);
   va_end (args);
 }
 
@@ -466,18 +520,22 @@ void
 void
 lex_error_expecting_valist (struct lexer *lexer, va_list args)
 {
-  enum { MAX_OPTIONS = 9 };
-  const char *options[MAX_OPTIONS];
-  int n = 0;
-  while (n < MAX_OPTIONS)
+  const char **options = NULL;
+  size_t allocated = 0;
+  size_t n = 0;
+
+  for (;;)
     {
       const char *option = va_arg (args, const char *);
       if (!option)
         break;
 
+      if (n >= allocated)
+        options = x2nrealloc (options, &allocated, sizeof *options);
       options[n++] = option;
     }
   lex_error_expecting_array (lexer, options, n);
+  free (options);
 }
 
 void
@@ -490,62 +548,82 @@ lex_error_expecting_array (struct lexer *lexer, const char **options, size_t n)
       break;
 
     case 1:
-      lex_error (lexer, _("expecting %s"), options[0]);
+      lex_error (lexer, _("Syntax error expecting %s."), options[0]);
       break;
 
     case 2:
-      lex_error (lexer, _("expecting %s or %s"), options[0], options[1]);
+      lex_error (lexer, _("Syntax error expecting %s or %s."),
+                 options[0], options[1]);
       break;
 
     case 3:
-      lex_error (lexer, _("expecting %s, %s, or %s"), options[0], options[1],
-                 options[2]);
+      lex_error (lexer, _("Syntax error expecting %s, %s, or %s."),
+                 options[0], options[1], options[2]);
       break;
 
     case 4:
-      lex_error (lexer, _("expecting %s, %s, %s, or %s"),
+      lex_error (lexer, _("Syntax error expecting %s, %s, %s, or %s."),
                  options[0], options[1], options[2], options[3]);
       break;
 
     case 5:
-      lex_error (lexer, _("expecting %s, %s, %s, %s, or %s"),
+      lex_error (lexer, _("Syntax error expecting %s, %s, %s, %s, or %s."),
                  options[0], options[1], options[2], options[3], options[4]);
       break;
 
     case 6:
-      lex_error (lexer, _("expecting %s, %s, %s, %s, %s, or %s"),
+      lex_error (lexer, _("Syntax error expecting %s, %s, %s, %s, %s, or %s."),
                  options[0], options[1], options[2], options[3], options[4],
                  options[5]);
       break;
 
     case 7:
-      lex_error (lexer, _("expecting %s, %s, %s, %s, %s, %s, or %s"),
+      lex_error (lexer, _("Syntax error expecting %s, %s, %s, %s, %s, %s, "
+                          "or %s."),
                  options[0], options[1], options[2], options[3], options[4],
                  options[5], options[6]);
       break;
 
     case 8:
-      lex_error (lexer, _("expecting %s, %s, %s, %s, %s, %s, %s, or %s"),
+      lex_error (lexer, _("Syntax error expecting %s, %s, %s, %s, %s, %s, %s, "
+                          "or %s."),
                  options[0], options[1], options[2], options[3], options[4],
                  options[5], options[6], options[7]);
       break;
 
     default:
-      lex_error (lexer, NULL);
+      {
+        struct string s = DS_EMPTY_INITIALIZER;
+        for (size_t i = 0; i < n; i++)
+          {
+            if (i > 0)
+              ds_put_cstr (&s, ", ");
+            ds_put_cstr (&s, options[i]);
+          }
+        lex_error (lexer, _("Syntax error expecting one of the following: %s."),
+                   ds_cstr (&s));
+        ds_destroy (&s);
+      }
+      break;
     }
 }
 
 /* Reports an error to the effect that subcommand SBC may only be specified
-   once.
-
-   This function does not take a lexer as an argument or use lex_error(),
-   because the result would ordinarily just be redundant: "Syntax error at
-   SUBCOMMAND: Subcommand SUBCOMMAND may only be specified once.", which does
-   not help the user find the error. */
+   once. */
 void
-lex_sbc_only_once (const char *sbc)
+lex_sbc_only_once (struct lexer *lexer, const char *sbc)
 {
-  msg (SE, _("Subcommand %s may only be specified once."), sbc);
+  int ofs = lex_ofs (lexer) - 1;
+  if (lex_ofs_token (lexer, ofs)->type == T_EQUALS)
+    ofs--;
+
+  /* lex_ofs_at_phrase__() handles subcommand names that are keywords, such as
+     BY. */
+  if (lex_ofs_at_phrase__ (lexer, ofs, sbc, NULL))
+    lex_ofs_error (lexer, ofs, ofs,
+                   _("Subcommand %s may only be specified once."), sbc);
+  else
+    msg (SE, _("Subcommand %s may only be specified once."), sbc);
 }
 
 /* Reports an error to the effect that subcommand SBC is missing.
@@ -555,9 +633,10 @@ lex_sbc_only_once (const char *sbc)
    command has been parsed, and so lex_error() would always report "Syntax
    error at end of command", which does not help the user find the error. */
 void
-lex_sbc_missing (const char *sbc)
+lex_sbc_missing (struct lexer *lexer, const char *sbc)
 {
-  msg (SE, _("Required subcommand %s was not specified."), sbc);
+  lex_ofs_error (lexer, 0, lex_max_ofs (lexer),
+                 _("Required subcommand %s was not specified."), sbc);
 }
 
 /* Reports an error to the effect that specification SPEC may only be specified
@@ -565,7 +644,7 @@ lex_sbc_missing (const char *sbc)
 void
 lex_spec_only_once (struct lexer *lexer, const char *sbc, const char *spec)
 {
-  lex_error (lexer, _("%s may only be specified once within subcommand %s"),
+  lex_error (lexer, _("%s may only be specified once within subcommand %s."),
              spec, sbc);
 }
 
@@ -574,36 +653,18 @@ lex_spec_only_once (struct lexer *lexer, const char *sbc, const char *spec)
 void
 lex_spec_missing (struct lexer *lexer, const char *sbc, const char *spec)
 {
-  lex_error (lexer, _("Required %s specification missing from %s subcommand"),
-             sbc, spec);
+  lex_error (lexer, _("Required %s specification missing from %s subcommand."),
+             spec, sbc);
 }
 
-/* Prints a syntax error message containing the current token and
-   given message MESSAGE (if non-null). */
+/* Prints a syntax error message for the span of tokens with offsets OFS0
+   through OFS1, inclusive, within the current command in LEXER, adding message
+   MESSAGE (if non-null) with the given ARGS. */
 void
-lex_next_error_valist (struct lexer *lexer, int n0, int n1,
-                       const char *format, va_list args)
+lex_ofs_msg_valist (struct lexer *lexer, enum msg_class class,
+                    int ofs0, int ofs1, const char *format, va_list args)
 {
-  struct lex_source *src = lex_source__ (lexer);
-
-  if (src != NULL)
-    lex_source_error_valist (src, n0, n1, format, args);
-  else
-    {
-      struct string s;
-
-      ds_init_empty (&s);
-      ds_put_format (&s, _("Syntax error at end of input"));
-      if (format != NULL)
-        {
-          ds_put_cstr (&s, ": ");
-          ds_put_vformat (&s, format, args);
-        }
-      if (ds_last (&s) != '.')
-        ds_put_byte (&s, '.');
-      msg (SE, "%s", ds_cstr (&s));
-      ds_destroy (&s);
-    }
+  lex_source_msg_valist (lex_source__ (lexer), class, ofs0, ofs1, format, args);
 }
 
 /* Checks that we're at end of command.
@@ -615,7 +676,7 @@ lex_end_of_command (struct lexer *lexer)
 {
   if (lex_token (lexer) != T_ENDCMD && lex_token (lexer) != T_STOP)
     {
-      lex_error (lexer, _("expecting end of command"));
+      lex_error (lexer, _("Syntax error expecting end of command."));
       return CMD_FAILURE;
     }
   else
@@ -817,7 +878,7 @@ lex_force_string (struct lexer *lexer)
     return true;
   else
     {
-      lex_error (lexer, _("expecting string"));
+      lex_error (lexer, _("Syntax error expecting string."));
       return false;
     }
 }
@@ -846,7 +907,7 @@ lex_force_int (struct lexer *lexer)
     return true;
   else
     {
-      lex_error (lexer, _("expecting integer"));
+      lex_error (lexer, _("Syntax error expecting integer."));
       return false;
     }
 }
@@ -873,23 +934,25 @@ lex_force_int_range (struct lexer *lexer, const char *name, long min, long max)
       /* Weird, maybe a bug in the caller.  Just report that we needed an
          integer. */
       if (name)
-        lex_error (lexer, _("Integer expected for %s."), name);
+        lex_error (lexer, _("Syntax error expecting integer for %s."), name);
       else
-        lex_error (lexer, _("Integer expected."));
+        lex_error (lexer, _("Syntax error expecting integer."));
     }
   else if (min == max)
     {
       if (name)
-        lex_error (lexer, _("Expected %ld for %s."), min, name);
+        lex_error (lexer, _("Syntax error expecting %ld for %s."), min, name);
       else
-        lex_error (lexer, _("Expected %ld."), min);
+        lex_error (lexer, _("Syntax error expecting %ld."), min);
     }
   else if (min + 1 == max)
     {
       if (name)
-        lex_error (lexer, _("Expected %ld or %ld for %s."), min, min + 1, name);
+        lex_error (lexer, _("Syntax error expecting %ld or %ld for %s."),
+                   min, min + 1, name);
       else
-        lex_error (lexer, _("Expected %ld or %ld."), min, min + 1);
+        lex_error (lexer, _("Syntax error expecting %ld or %ld."),
+                   min, min + 1);
     }
   else
     {
@@ -900,10 +963,12 @@ lex_force_int_range (struct lexer *lexer, const char *name, long min, long max)
         {
           if (name)
             lex_error (lexer,
-                       _("Expected integer between %ld and %ld for %s."),
+                       _("Syntax error expecting integer "
+                         "between %ld and %ld for %s."),
                        min, max, name);
           else
-            lex_error (lexer, _("Expected integer between %ld and %ld."),
+            lex_error (lexer, _("Syntax error expecting integer "
+                                "between %ld and %ld."),
                        min, max);
         }
       else if (report_lower_bound)
@@ -911,44 +976,53 @@ lex_force_int_range (struct lexer *lexer, const char *name, long min, long max)
           if (min == 0)
             {
               if (name)
-                lex_error (lexer, _("Expected non-negative integer for %s."),
+                lex_error (lexer, _("Syntax error expecting "
+                                    "non-negative integer for %s."),
                            name);
               else
-                lex_error (lexer, _("Expected non-negative integer."));
+                lex_error (lexer, _("Syntax error expecting "
+                                    "non-negative integer."));
             }
           else if (min == 1)
             {
               if (name)
-                lex_error (lexer, _("Expected positive integer for %s."),
+                lex_error (lexer, _("Syntax error expecting "
+                                    "positive integer for %s."),
                            name);
               else
-                lex_error (lexer, _("Expected positive integer."));
+                lex_error (lexer, _("Syntax error expecting "
+                                    "positive integer."));
             }
           else
             {
               if (name)
-                lex_error (lexer, _("Expected integer %ld or greater for %s."),
+                lex_error (lexer, _("Syntax error expecting "
+                                    "integer %ld or greater for %s."),
                            min, name);
               else
-                lex_error (lexer, _("Expected integer %ld or greater."), min);
+                lex_error (lexer, _("Syntax error expecting "
+                                    "integer %ld or greater."), min);
             }
         }
       else if (report_upper_bound)
         {
           if (name)
             lex_error (lexer,
-                       _("Expected integer less than or equal to %ld for %s."),
+                       _("Syntax error expecting integer less than or equal "
+                         "to %ld for %s."),
                        max, name);
           else
-            lex_error (lexer, _("Expected integer less than or equal to %ld."),
+            lex_error (lexer, _("Syntax error expecting integer less than or "
+                                "equal to %ld."),
                        max);
         }
       else
         {
           if (name)
-            lex_error (lexer, _("Integer expected for %s."), name);
+            lex_error (lexer, _("Syntax error expecting integer for %s."),
+                       name);
           else
-            lex_error (lexer, _("Integer expected."));
+            lex_error (lexer, _("Syntax error expecting integer."));
         }
     }
   return false;
@@ -962,7 +1036,262 @@ lex_force_num (struct lexer *lexer)
   if (lex_is_number (lexer))
     return true;
 
-  lex_error (lexer, _("expecting number"));
+  lex_error (lexer, _("Syntax error expecting number."));
+  return false;
+}
+
+/* If the current token is an number in the closed range [MIN,MAX], does
+   nothing and returns true.  Otherwise, reports an error and returns false.
+   If NAME is nonnull, then it is used in the error message. */
+bool
+lex_force_num_range_closed (struct lexer *lexer, const char *name,
+                            double min, double max)
+{
+  bool is_number = lex_is_number (lexer);
+  bool too_small = is_number && lex_number (lexer) < min;
+  bool too_big = is_number && lex_number (lexer) > max;
+  if (is_number && !too_small && !too_big)
+    return true;
+
+  if (min > max)
+    {
+      /* Weird, maybe a bug in the caller.  Just report that we needed an
+         number. */
+      if (name)
+        lex_error (lexer, _("Syntax error expecting number for %s."), name);
+      else
+        lex_error (lexer, _("Syntax error expecting number."));
+    }
+  else if (min == max)
+    {
+      if (name)
+        lex_error (lexer, _("Syntax error expecting number %g for %s."),
+                   min, name);
+      else
+        lex_error (lexer, _("Syntax error expecting number %g."), min);
+    }
+  else
+    {
+      bool report_lower_bound = min > -DBL_MAX || too_small;
+      bool report_upper_bound = max < DBL_MAX || too_big;
+
+      if (report_lower_bound && report_upper_bound)
+        {
+          if (name)
+            lex_error (lexer,
+                       _("Syntax error expecting number "
+                         "between %g and %g for %s."),
+                       min, max, name);
+          else
+            lex_error (lexer, _("Syntax error expecting number "
+                                "between %g and %g."),
+                       min, max);
+        }
+      else if (report_lower_bound)
+        {
+          if (min == 0)
+            {
+              if (name)
+                lex_error (lexer, _("Syntax error expecting "
+                                    "non-negative number for %s."),
+                           name);
+              else
+                lex_error (lexer, _("Syntax error expecting "
+                                    "non-negative number."));
+            }
+          else
+            {
+              if (name)
+                lex_error (lexer, _("Syntax error expecting number "
+                                    "%g or greater for %s."),
+                           min, name);
+              else
+                lex_error (lexer, _("Syntax error expecting number "
+                                    "%g or greater."), min);
+            }
+        }
+      else if (report_upper_bound)
+        {
+          if (name)
+            lex_error (lexer,
+                       _("Syntax error expecting number "
+                         "less than or equal to %g for %s."),
+                       max, name);
+          else
+            lex_error (lexer, _("Syntax error expecting number "
+                                "less than or equal to %g."),
+                       max);
+        }
+      else
+        {
+          if (name)
+            lex_error (lexer, _("Syntax error expecting number for %s."), name);
+          else
+            lex_error (lexer, _("Syntax error expecting number."));
+        }
+    }
+  return false;
+}
+
+/* If the current token is an number in the half-open range [MIN,MAX), does
+   nothing and returns true.  Otherwise, reports an error and returns false.
+   If NAME is nonnull, then it is used in the error message. */
+bool
+lex_force_num_range_halfopen (struct lexer *lexer, const char *name,
+                              double min, double max)
+{
+  bool is_number = lex_is_number (lexer);
+  bool too_small = is_number && lex_number (lexer) < min;
+  bool too_big = is_number && lex_number (lexer) >= max;
+  if (is_number && !too_small && !too_big)
+    return true;
+
+  if (min >= max)
+    {
+      /* Weird, maybe a bug in the caller.  Just report that we needed an
+         number. */
+      if (name)
+        lex_error (lexer, _("Syntax error expecting number for %s."), name);
+      else
+        lex_error (lexer, _("Syntax error expecting number."));
+    }
+  else
+    {
+      bool report_lower_bound = min > -DBL_MAX || too_small;
+      bool report_upper_bound = max < DBL_MAX || too_big;
+
+      if (report_lower_bound && report_upper_bound)
+        {
+          if (name)
+            lex_error (lexer, _("Syntax error expecting number "
+                                "in [%g,%g) for %s."),
+                       min, max, name);
+          else
+            lex_error (lexer, _("Syntax error expecting number in [%g,%g)."),
+                       min, max);
+        }
+      else if (report_lower_bound)
+        {
+          if (min == 0)
+            {
+              if (name)
+                lex_error (lexer, _("Syntax error expecting "
+                                    "non-negative number for %s."),
+                           name);
+              else
+                lex_error (lexer, _("Syntax error expecting "
+                                    "non-negative number."));
+            }
+          else
+            {
+              if (name)
+                lex_error (lexer, _("Syntax error expecting "
+                                    "number %g or greater for %s."),
+                           min, name);
+              else
+                lex_error (lexer, _("Syntax error expecting "
+                                    "number %g or greater."), min);
+            }
+        }
+      else if (report_upper_bound)
+        {
+          if (name)
+            lex_error (lexer,
+                       _("Syntax error expecting "
+                         "number less than %g for %s."), max, name);
+          else
+            lex_error (lexer, _("Syntax error expecting "
+                                "number less than %g."), max);
+        }
+      else
+        {
+          if (name)
+            lex_error (lexer, _("Syntax error expecting number for %s."), name);
+          else
+            lex_error (lexer, _("Syntax error expecting number."));
+        }
+    }
+  return false;
+}
+
+/* If the current token is an number in the open range (MIN,MAX), does
+   nothing and returns true.  Otherwise, reports an error and returns false.
+   If NAME is nonnull, then it is used in the error message. */
+bool
+lex_force_num_range_open (struct lexer *lexer, const char *name,
+                          double min, double max)
+{
+  bool is_number = lex_is_number (lexer);
+  bool too_small = is_number && lex_number (lexer) <= min;
+  bool too_big = is_number && lex_number (lexer) >= max;
+  if (is_number && !too_small && !too_big)
+    return true;
+
+  if (min >= max)
+    {
+      /* Weird, maybe a bug in the caller.  Just report that we needed an
+         number. */
+      if (name)
+        lex_error (lexer, _("Syntax error expecting number for %s."), name);
+      else
+        lex_error (lexer, _("Syntax error expecting number."));
+    }
+  else
+    {
+      bool report_lower_bound = min > -DBL_MAX || too_small;
+      bool report_upper_bound = max < DBL_MAX || too_big;
+
+      if (report_lower_bound && report_upper_bound)
+        {
+          if (name)
+            lex_error (lexer, _("Syntax error expecting number "
+                                "in (%g,%g) for %s."),
+                       min, max, name);
+          else
+            lex_error (lexer, _("Syntax error expecting number "
+                                "in (%g,%g)."), min, max);
+        }
+      else if (report_lower_bound)
+        {
+          if (min == 0)
+            {
+              if (name)
+                lex_error (lexer, _("Syntax error expecting "
+                                    "positive number for %s."), name);
+              else
+                lex_error (lexer, _("Syntax error expecting "
+                                    "positive number."));
+            }
+          else
+            {
+              if (name)
+                lex_error (lexer, _("Syntax error expecting number "
+                                    "greater than %g for %s."),
+                           min, name);
+              else
+                lex_error (lexer, _("Syntax error expecting number "
+                                    "greater than %g."), min);
+            }
+        }
+      else if (report_upper_bound)
+        {
+          if (name)
+            lex_error (lexer, _("Syntax error expecting number "
+                                "less than %g for %s."),
+                       max, name);
+          else
+            lex_error (lexer, _("Syntax error expecting number "
+                                "less than %g."), max);
+        }
+      else
+        {
+          if (name)
+            lex_error (lexer, _("Syntax error expecting number "
+                                "for %s."), name);
+          else
+            lex_error (lexer, _("Syntax error expecting number."));
+        }
+    }
   return false;
 }
 
@@ -974,7 +1303,7 @@ lex_force_id (struct lexer *lexer)
   if (lex_token (lexer) == T_ID)
     return true;
 
-  lex_error (lexer, _("expecting identifier"));
+  lex_error (lexer, _("Syntax error expecting identifier."));
   return false;
 }
 
@@ -1151,6 +1480,25 @@ lex_ofs (const struct lexer *lexer)
   return src ? src->parse_ofs : 0;
 }
 
+/* Returns the offset of the last token in the current command. */
+int
+lex_max_ofs (const struct lexer *lexer)
+{
+  struct lex_source *src = lex_source__ (lexer);
+  if (!src)
+    return 0;
+
+  int ofs = MAX (1, src->n_parse) - 1;
+  for (;;)
+    {
+      enum token_type type = lex_source_ofs__ (src, ofs)->token.type;
+      if (type == T_ENDCMD || type == T_STOP)
+        return ofs;
+
+      ofs++;
+    }
+}
+
 /* Returns the token within LEXER's current command with offset OFS.  Use
    lex_ofs() to find out the offset of the current token. */
 const struct token *
@@ -1221,15 +1569,37 @@ lex_ofs_end_point (const struct lexer *lexer, int ofs)
 
 /* Returns the text of the syntax in tokens N0 ahead of the current one,
    through N1 ahead of the current one, inclusive.  (For example, if N0 and N1
-   are both zero, this requests the syntax for the current token.)  The caller
-   must eventually free the returned string (with free()).  The syntax is
-   encoded in UTF-8 and in the original form supplied to the lexer so that, for
-   example, it may include comments, spaces, and new-lines if it spans multiple
-   tokens.  Macro expansion, however, has already been performed. */
+   are both zero, this requests the syntax for the current token.)
+
+   The caller must eventually free the returned string (with free()).  The
+   syntax is encoded in UTF-8 and in the original form supplied to the lexer so
+   that, for example, it may include comments, spaces, and new-lines if it
+   spans multiple tokens.  Macro expansion, however, has already been
+   performed. */
 char *
 lex_next_representation (const struct lexer *lexer, int n0, int n1)
 {
-  return lex_source_get_syntax__ (lex_source__ (lexer), n0, n1);
+  const struct lex_source *src = lex_source__ (lexer);
+  return (src
+          ? lex_source_syntax__ (src, n0 + src->parse_ofs, n1 + src->parse_ofs)
+          : xstrdup (""));
+}
+
+
+/* Returns the text of the syntax in tokens with offsets OFS0 to OFS1,
+   inclusive.  (For example, if OFS0 and OFS1 are both zero, this requests the
+   syntax for the first token in the current command.)
+
+   The caller must eventually free the returned string (with free()).  The
+   syntax is encoded in UTF-8 and in the original form supplied to the lexer so
+   that, for example, it may include comments, spaces, and new-lines if it
+   spans multiple tokens.  Macro expansion, however, has already been
+   performed. */
+char *
+lex_ofs_representation (const struct lexer *lexer, int ofs0, int ofs1)
+{
+  const struct lex_source *src = lex_source__ (lexer);
+  return src ? lex_source_syntax__ (src, ofs0, ofs1) : xstrdup ("");
 }
 
 /* Returns true if the token N ahead of the current one was produced by macro
@@ -1265,22 +1635,31 @@ lex_tokens_match (const struct token *actual, const struct token *expected)
     }
 }
 
-static size_t
-lex_at_phrase__ (struct lexer *lexer, const char *s)
+static bool
+lex_ofs_at_phrase__ (struct lexer *lexer, int ofs, const char *s,
+                     size_t *n_matchedp)
 {
   struct string_lexer slex;
   struct token token;
 
-  size_t i = 0;
+  size_t n_matched = 0;
+  bool all_matched = true;
   string_lexer_init (&slex, s, strlen (s), SEG_MODE_INTERACTIVE, true);
   while (string_lexer_next (&slex, &token))
     {
-      bool match = lex_tokens_match (lex_next (lexer, i++), &token);
+      bool match = lex_tokens_match (lex_ofs_token (lexer, ofs + n_matched),
+                                     &token);
       token_uninit (&token);
       if (!match)
-        return 0;
+        {
+          all_matched = false;
+          break;
+        }
+      n_matched++;
     }
-  return i;
+  if (n_matchedp)
+    *n_matchedp = n_matched;
+  return all_matched;
 }
 
 /* If LEXER is positioned at the sequence of tokens that may be parsed from S,
@@ -1292,7 +1671,7 @@ lex_at_phrase__ (struct lexer *lexer, const char *s)
 bool
 lex_at_phrase (struct lexer *lexer, const char *s)
 {
-  return lex_at_phrase__ (lexer, s) > 0;
+  return lex_ofs_at_phrase__ (lexer, lex_ofs (lexer), s, NULL);
 }
 
 /* If LEXER is positioned at the sequence of tokens that may be parsed from S,
@@ -1304,10 +1683,29 @@ lex_at_phrase (struct lexer *lexer, const char *s)
 bool
 lex_match_phrase (struct lexer *lexer, const char *s)
 {
-  size_t n = lex_at_phrase__ (lexer, s);
-  if (n > 0)
-    lex_get_n (lexer, n);
-  return n > 0;
+  size_t n_matched;
+  if (!lex_ofs_at_phrase__ (lexer, lex_ofs (lexer), s, &n_matched))
+    return false;
+  lex_get_n (lexer, n_matched);
+  return true;
+}
+
+/* If LEXER is positioned at the sequence of tokens that may be parsed from S,
+   skips it and returns true.  Otherwise, issues an error and returns false.
+
+   S may consist of an arbitrary sequence of tokens, e.g. "KRUSKAL-WALLIS",
+   "2SLS", or "END INPUT PROGRAM".  Identifiers may be abbreviated to their
+   first three letters. */
+bool
+lex_force_match_phrase (struct lexer *lexer, const char *s)
+{
+  size_t n_matched;
+  bool ok = lex_ofs_at_phrase__ (lexer, lex_ofs (lexer), s, &n_matched);
+  if (ok)
+    lex_get_n (lexer, n_matched);
+  else
+    lex_next_error (lexer, 0, n_matched, _("Syntax error expecting `%s'."), s);
+  return ok;
 }
 
 /* Returns the 1-based line number of the source text at the byte OFFSET in
@@ -1373,6 +1771,7 @@ lex_token_location (const struct lex_source *src,
     .file_name = intern_new_if_nonnull (src->reader->file_name),
     .start = lex_token_start_point (src, t0),
     .end = lex_token_end_point (src, t1),
+    .src = CONST_CAST (struct lex_source *, src),
   };
 }
 
@@ -1386,11 +1785,11 @@ lex_token_location_rw (const struct lex_source *src,
 }
 
 static struct msg_location *
-lex_source_get_location (const struct lex_source *src, int n0, int n1)
+lex_source_get_location (const struct lex_source *src, int ofs0, int ofs1)
 {
   return lex_token_location_rw (src,
-                                lex_source_next__ (src, n0),
-                                lex_source_next__ (src, n1));
+                                lex_source_ofs__ (src, ofs0),
+                                lex_source_ofs__ (src, ofs1));
 }
 
 /* Returns the name of the syntax file from which the current command is drawn.
@@ -1500,9 +1899,11 @@ void
 lex_discard_noninteractive (struct lexer *lexer)
 {
   struct lex_source *src = lex_source__ (lexer);
-
   if (src != NULL)
     {
+      if (src->reader->error == LEX_ERROR_IGNORE)
+        return;
+
       lex_stage_clear (&src->pp);
       lex_stage_clear (&src->merge);
       lex_source_clear_parse (src);
@@ -1557,32 +1958,39 @@ lex_source__ (const struct lexer *lexer)
           : ll_data (ll_head (&lexer->sources), struct lex_source, ll));
 }
 
-/* Returns the text of the syntax in SRC for tokens N0 ahead of the current
-   one, through N1 ahead of the current one, inclusive.  (For example, if N0
-   and N1 are both zero, this requests the syntax for the current token.)  The
-   caller must eventually free the returned string (with free()).  The syntax
-   is encoded in UTF-8 and in the original form supplied to the lexer so that,
-   for example, it may include comments, spaces, and new-lines if it spans
-   multiple tokens.  Macro expansion, however, has already been performed. */
+const struct lex_source *
+lex_source (const struct lexer *lexer)
+{
+  return lex_source__ (lexer);
+}
+
+/* Returns the text of the syntax in SRC for tokens with offsets OFS0 through
+   OFS1 in the current command, inclusive.  (For example, if OFS0 and OFS1 are
+   both zero, this requests the syntax for the first token in the current
+   command.)  The caller must eventually free the returned string (with
+   free()).  The syntax is encoded in UTF-8 and in the original form supplied
+   to the lexer so that, for example, it may include comments, spaces, and
+   new-lines if it spans multiple tokens.  Macro expansion, however, has
+   already been performed. */
 static char *
-lex_source_get_syntax__ (const struct lex_source *src, int n0, int n1)
+lex_source_syntax__ (const struct lex_source *src, int ofs0, int ofs1)
 {
   struct string s = DS_EMPTY_INITIALIZER;
-  for (size_t i = n0; i <= n1; )
+  for (size_t i = ofs0; i <= ofs1; )
     {
       /* Find [I,J) as the longest sequence of tokens not produced by macro
          expansion, or otherwise the longest sequence expanded from a single
          macro call. */
-      const struct lex_token *first = lex_source_next__ (src, i);
+      const struct lex_token *first = lex_source_ofs__ (src, i);
       size_t j;
-      for (j = i + 1; j <= n1; j++)
+      for (j = i + 1; j <= ofs1; j++)
         {
-          const struct lex_token *cur = lex_source_next__ (src, j);
+          const struct lex_token *cur = lex_source_ofs__ (src, j);
           if ((first->macro_rep != NULL) != (cur->macro_rep != NULL)
               || first->macro_rep != cur->macro_rep)
             break;
         }
-      const struct lex_token *last = lex_source_next__ (src, j - 1);
+      const struct lex_token *last = lex_source_ofs__ (src, j - 1);
 
       /* Now add the syntax for this sequence of tokens to SRC. */
       if (!ds_is_empty (&s))
@@ -1607,10 +2015,10 @@ lex_source_get_syntax__ (const struct lex_source *src, int n0, int n1)
 }
 
 static bool
-lex_source_contains_macro_call (struct lex_source *src, int n0, int n1)
+lex_source_contains_macro_call (struct lex_source *src, int ofs0, int ofs1)
 {
-  for (size_t i = n0; i <= n1; i++)
-    if (lex_source_next__ (src, i)->macro_rep)
+  for (int i = ofs0; i <= ofs1; i++)
+    if (lex_source_ofs__ (src, i)->macro_rep)
       return true;
   return false;
 }
@@ -1625,13 +2033,13 @@ lex_source_contains_macro_call (struct lex_source *src, int n0, int n1)
 
    The caller must not modify or free the returned string. */
 static struct substring
-lex_source_get_macro_call (struct lex_source *src, int n0, int n1)
+lex_source_get_macro_call (struct lex_source *src, int ofs0, int ofs1)
 {
-  if (!lex_source_contains_macro_call (src, n0, n1))
+  if (!lex_source_contains_macro_call (src, ofs0, ofs1))
     return ss_empty ();
 
-  const struct lex_token *token0 = lex_source_next__ (src, n0);
-  const struct lex_token *token1 = lex_source_next__ (src, MAX (n0, n1));
+  const struct lex_token *token0 = lex_source_ofs__ (src, ofs0);
+  const struct lex_token *token1 = lex_source_ofs__ (src, MAX (ofs0, ofs1));
   size_t start = token0->token_pos;
   size_t end = token1->token_pos + token1->token_len;
 
@@ -1639,63 +2047,39 @@ lex_source_get_macro_call (struct lex_source *src, int n0, int n1)
 }
 
 static void
-lex_source_error_valist (struct lex_source *src, int n0, int n1,
-                         const char *format, va_list args)
+lex_source_msg_valist (struct lex_source *src, enum msg_class class,
+                       int ofs0, int ofs1, const char *format, va_list args)
 {
-  const struct lex_token *token;
-  struct string s;
-
-  ds_init_empty (&s);
+  struct string s = DS_EMPTY_INITIALIZER;
 
-  token = lex_source_next__ (src, n0);
-  if (token->token.type == T_ENDCMD)
-    ds_put_cstr (&s, _("Syntax error at end of command"));
-  else
+  if (src)
     {
-      /* Get the syntax that caused the error. */
-      char *raw_syntax = lex_source_get_syntax__ (src, n0, n1);
-      char syntax[64];
-      str_ellipsize (ss_cstr (raw_syntax), syntax, sizeof syntax);
-      free (raw_syntax);
-
       /* Get the macro call(s) that expanded to the syntax that caused the
          error. */
       char call[64];
-      str_ellipsize (lex_source_get_macro_call (src, n0, n1),
+      str_ellipsize (lex_source_get_macro_call (src, ofs0, ofs1),
                      call, sizeof call);
-
-      if (syntax[0])
-        {
-          if (call[0])
-            ds_put_format (&s,
-                           _("Syntax error at `%s' (in expansion of `%s')"),
-                           syntax, call);
-          else
-            ds_put_format (&s, _("Syntax error at `%s'"), syntax);
-        }
-      else
-        {
-          if (call[0])
-            ds_put_format (&s, _("Syntax error in syntax expanded from `%s'"),
-                           call);
-          else
-            ds_put_cstr (&s, _("Syntax error"));
-        }
+      if (call[0])
+        ds_put_format (&s, _("In syntax expanded from `%s'"), call);
     }
+  else
+    ds_put_cstr (&s, _("At end of input"));
 
+  if (!ds_is_empty (&s))
+    ds_put_cstr (&s, ": ");
   if (format)
-    {
-      ds_put_cstr (&s, ": ");
-      ds_put_vformat (&s, format, args);
-    }
+    ds_put_vformat (&s, format, args);
+  else
+    ds_put_cstr (&s, _("Syntax error."));
+
   if (ds_last (&s) != '.')
     ds_put_byte (&s, '.');
 
   struct msg *m = xmalloc (sizeof *m);
   *m = (struct msg) {
-    .category = MSG_C_SYNTAX,
-    .severity = MSG_S_ERROR,
-    .location = lex_source_get_location (src, n0, n1),
+    .category = msg_class_to_category (class),
+    .severity = msg_class_to_severity (class),
+    .location = src ? lex_source_get_location (src, ofs0, ofs1) : NULL,
     .text = ds_steal_cstr (&s),
   };
   msg_emit (m);
@@ -1709,8 +2093,7 @@ lex_get_error (struct lex_source *src, const struct lex_token *token)
                  syntax, sizeof syntax);
 
   struct string s = DS_EMPTY_INITIALIZER;
-  ds_put_format (&s, _("Syntax error at `%s'"), syntax);
-  ds_put_format (&s, ": %s", token->token.string.string);
+  ds_put_cstr (&s, token->token.string.string);
 
   struct msg *m = xmalloc (sizeof *m);
   *m = (struct msg) {
@@ -2093,7 +2476,7 @@ lex_set_message_handler (struct lexer *lexer,
   msg_set_handler (&msg_handler);
 }
 
-void
+struct lex_source *
 lex_source_ref (const struct lex_source *src_)
 {
   struct lex_source *src = CONST_CAST (struct lex_source *, src_);
@@ -2102,6 +2485,7 @@ lex_source_ref (const struct lex_source *src_)
       assert (src->n_refs > 0);
       src->n_refs++;
     }
+  return src;
 }
 
 void
@@ -2247,9 +2631,7 @@ lex_reader_for_substring_nocopy (struct substring s, const char *encoding)
 struct lex_reader *
 lex_reader_for_string (const char *s, const char *encoding)
 {
-  struct substring ss;
-  ss_alloc_substring (&ss, ss_cstr (s));
-  return lex_reader_for_substring_nocopy (ss, encoding);
+  return lex_reader_for_substring_nocopy (ss_clone (ss_cstr (s)), encoding);
 }
 
 /* Formats FORMAT as a printf()-like format string and creates and returns a
@@ -2309,6 +2691,13 @@ lex_source_get_line (const struct lex_source *src, int line)
     return ss_empty ();
 
   size_t ofs = src->lines[line - 1];
-  size_t end = line >= src->n_lines ? src->length : src->lines[line];
+  size_t end;
+  if (line < src->n_lines)
+    end = src->lines[line];
+  else
+    {
+      const char *newline = memchr (src->buffer + ofs, '\n', src->length - ofs);
+      end = newline ? newline - src->buffer : src->length;
+    }
   return ss_buffer (&src->buffer[ofs], end - ofs);
 }