[misc 11/18] identifier: New function token_type_to_string().

[Ben Pfaff]

This is useful for debugging and testing code.
---
 src/data/identifier.c |   16 ++++++++++
 src/data/identifier.h |   79 ++++++++++++++++++++++++++----------------------
 2 files changed, 59 insertions(+), 36 deletions(-)

diff --git a/src/data/identifier.c b/src/data/identifier.c
index 1e149b8..498f5ea 100644
--- a/src/data/identifier.c
+++ b/src/data/identifier.c
@@ -31,6 +31,22 @@
 
 #include "gl/c-ctype.h"
 
+/* Tokens. */
+
+const char *
+token_type_to_string (enum token_type type)
+{
+  switch (type)
+    {
+#define TOKEN_TYPE(TYPE) case T_##TYPE: return #TYPE;
+      TOKEN_TYPES
+#undef TOKEN_TYPE
+    case TOKEN_N_TYPES:
+    default:
+      return "unknown token type";
+    }
+}
+
 /* Recognizing identifiers. */
 
 static bool
diff --git a/src/data/identifier.h b/src/data/identifier.h
index 02fc0db..fe030d1 100644
--- a/src/data/identifier.h
+++ b/src/data/identifier.h
@@ -22,47 +22,54 @@
 #include <unitypes.h>
 #include "libpspp/str.h"
 
+#define TOKEN_TYPES                                                     \
+    TOKEN_TYPE(ID)                         /* Identifier. */            \
+    TOKEN_TYPE(POS_NUM)                    /* Positive number. */       \
+    TOKEN_TYPE(NEG_NUM)                    /* Negative number. */       \
+    TOKEN_TYPE(STRING)                     /* Quoted string. */         \
+    TOKEN_TYPE(STOP)                       /* End of input. */          \
+                                                                        \
+    TOKEN_TYPE(ENDCMD)                     /* . */                      \
+    TOKEN_TYPE(PLUS)                       /* + */                      \
+    TOKEN_TYPE(DASH)                       /* - */                      \
+    TOKEN_TYPE(ASTERISK)                   /* * */                      \
+    TOKEN_TYPE(SLASH)                      /* / */                      \
+    TOKEN_TYPE(EQUALS)                     /* = */                      \
+    TOKEN_TYPE(LPAREN)                     /* ( */                      \
+    TOKEN_TYPE(RPAREN)                     /* ) */                      \
+    TOKEN_TYPE(LBRACK)                     /* [ */                      \
+    TOKEN_TYPE(RBRACK)                     /* ] */                      \
+    TOKEN_TYPE(COMMA)                      /* , */                      \
+                                                                        \
+    TOKEN_TYPE(AND)                        /* AND */                    \
+    TOKEN_TYPE(OR)                         /* OR */                     \
+    TOKEN_TYPE(NOT)                        /* NOT */                    \
+                                                                        \
+    TOKEN_TYPE(EQ)                         /* EQ */                     \
+    TOKEN_TYPE(GE)                         /* GE or >= */               \
+    TOKEN_TYPE(GT)                         /* GT or > */                \
+    TOKEN_TYPE(LE)                         /* LE or <= */               \
+    TOKEN_TYPE(LT)                         /* LT or < */                \
+    TOKEN_TYPE(NE)                         /* NE or ~= */               \
+                                                                        \
+    TOKEN_TYPE(ALL)                        /* ALL */                    \
+    TOKEN_TYPE(BY)                         /* BY */                     \
+    TOKEN_TYPE(TO)                         /* TO */                     \
+    TOKEN_TYPE(WITH)                       /* WITH */                   \
+                                                                        \
+    TOKEN_TYPE(EXP)                        /* ** */
+
 /* Token types. */
 enum token_type
   {
-    T_ID = 1,   /* Identifier. */
-    T_POS_NUM, /* Positive number. */
-    T_NEG_NUM, /* Negative number. */
-    T_STRING,  /* Quoted string. */
-    T_STOP,    /* End of input. */
-
-    T_ENDCMD,   /* End of command (e.g. '.'). */
-
-    T_PLUS,     /* + */
-    T_DASH,     /* - */
-    T_ASTERISK, /* * */
-    T_SLASH,    /* / */
-    T_EQUALS,   /* = */
-    T_LPAREN,   /* ( */
-    T_RPAREN,   /* ) */
-    T_LBRACK,   /* [ */
-    T_RBRACK,   /* ] */
-    T_COMMA,    /* , */
-
-    T_AND,     /* AND */
-    T_OR,      /* OR */
-    T_NOT,     /* NOT */
-
-    T_EQ,      /* EQ */
-    T_GE,      /* GE or >= */
-    T_GT,      /* GT or > */
-    T_LE,      /* LE or <= */
-    T_LT,      /* LT or < */
-    T_NE,      /* NE or ~= */
-
-    T_ALL,     /* ALL */
-    T_BY,      /* BY */
-    T_TO,      /* TO */
-    T_WITH,    /* WITH */
-
-    T_EXP,     /* ** */
+#define TOKEN_TYPE(TYPE) T_##TYPE,
+    TOKEN_TYPES
+    TOKEN_N_TYPES
+#undef TOKEN_TYPE
   };
 
+const char *token_type_to_string (enum token_type);
+
 /* Tokens. */
 bool lex_is_keyword (enum token_type);
 
-- 
1.7.1