main: add --list-output-formats option

Signed-off-by: Masatake YAMATO <[email protected]>

docs/man/ctags.1.rst

@@ -318,6 +318,8 @@ Output Format Options
 	the ctags executable is built with ``libjansson``.
 	See :ref:`ctags-json-output(5) <ctags-json-output(5)>` for more about ``json`` format.
 
+	See also ``--list-output-formats``.
+
 ``-e``
 	Same as ``--output-format=etags``.
 	Enable etags mode, which will create a tag file for use with the Emacs
@@ -1236,6 +1238,9 @@ Listing Options
 	definition.
 	See :ref:`ctags-optlib(7) <ctags-optlib(7)>`.
 
+``--list-output-formats``
+    Lists the output formats that can be used in ``--output-format`` option.
+
 ``--list-params[=(<language>|all)]``
 	Lists the parameters for either the specified *<language>* or ``all``
 	languages, and then exits.

main/options.c

@@ -440,6 +440,8 @@ static optionDescription LongOptionDescription [] = {
  {1,0,"       Output list of language mappings (both extensions and patterns)."},
  {1,0,"  --list-mline-regex-flags"},
  {1,0,"       Output list of flags which can be used in a multiline regex parser definition."},
+ {1,0,"  --list-output-formats"},
+ {1,0,"       Output list of output formats."},
  {1,0,"  --list-params[=(<language>|all)]"},
  {1,0,"       Output list of language parameters. This works with --machinable."},
  {0,0,"  --list-pseudo-tags"},
@@ -2314,6 +2316,13 @@ static void processListOperators (const char *const option CTAGS_ATTR_UNUSED,
 	exit (0);
 }
 
+static void processListOutputFormatsOption(const char *const option CTAGS_ATTR_UNUSED,
+										   const char *const parameter CTAGS_ATTR_UNUSED)
+{
+	printOutputFormats (localOption.withListHeader, localOption.machinable, stdout);
+	exit (0);
+}
+
 static void freeSearchPathList (searchPathList** pathList)
 {
 	stringListClear (*pathList);
@@ -2899,6 +2908,7 @@ static parametricOption ParametricOptions [] = {
 	{ "list-map-extensions",    processListMapExtensionsOption, true,   STAGE_ANY },
 	{ "list-map-patterns",      processListMapPatternsOption,   true,   STAGE_ANY },
 	{ "list-mline-regex-flags", processListMultilineRegexFlagsOptions, true, STAGE_ANY },
+	{ "list-output-formats",    processListOutputFormatsOption, true,   STAGE_ANY },
 	{ "list-params",            processListParametersOption,    true,   STAGE_ANY },
 	{ "list-pseudo-tags",       processListPseudoTagsOptions,   true,   STAGE_ANY },
 	{ "list-regex-flags",       processListRegexFlagsOptions,   true,   STAGE_ANY },

main/writer.c

@@ -9,6 +9,7 @@
 
 #include "general.h"
 
+#include "colprint_p.h"
 #include "debug.h"
 #include "entry_p.h"
 #include "options_p.h"
@@ -212,3 +213,43 @@ extern writerType getWrierForOutputFormat (const char *oformat)
 
 	return WRITER_UNKNOWN;
 }
+
+#define WRITER_COL_OFORMAT 0
+#define WRITER_COL_AVAILABLE 1
+#define WRITER_COL_NULLTAG 2
+
+static int writerColprintCompareLines (struct colprintLine *a , struct colprintLine *b)
+{
+	const char *a_oformat  = colprintLineGetColumn (a, WRITER_COL_OFORMAT);
+	const char *b_oformat  = colprintLineGetColumn (b, WRITER_COL_OFORMAT);
+
+	return strcmp(a_oformat, b_oformat);
+}
+
+extern struct colprintTable * writerColprintTableNew (void)
+{
+	return colprintTableNew ("L:OFORMAT", "R:AVAILABLE", "R:NULLTAG", NULL);
+}
+
+extern void printOutputFormats (bool withListHeader, bool machinable, FILE *fp)
+{
+	struct colprintTable * table = writerColprintTableNew ();
+
+	for (int i = 0; i < WRITER_COUNT; i++)
+	{
+		if (!writerTable[i])
+			continue;
+		if (!writerTable[i]->oformat)
+			continue;
+
+		struct colprintLine * line = colprintTableGetNewLine (table);
+		colprintLineAppendColumnCString (line, writerTable[i]->oformat);
+
+		colprintLineAppendColumnBool (line, writerTable[i]->writeEntry? true: false);
+		colprintLineAppendColumnBool (line, writerTable[i]->canPrintNullTag);
+	}
+
+	colprintTableSort (table, writerColprintCompareLines);
+	colprintTablePrint (table, 0, withListHeader, machinable, fp);
+	colprintTableDelete (table);
+}

main/writer_p.h

@@ -108,6 +108,7 @@ extern void writerCheckOptions (bool fieldsWereReset);
 extern bool writerPrintPtagByDefault (void);
 
 extern writerType getWrierForOutputFormat (const char *oformat);
+extern void printOutputFormats (bool withListHeader, bool machinable, FILE *fp);
 
 #ifdef _WIN32
 extern enum filenameSepOp getFilenameSeparator (enum filenameSepOp currentSetting);

man/ctags.1.rst.in

@@ -318,6 +318,8 @@ Output Format Options
 	the ctags executable is built with ``libjansson``.
 	See ctags-json-output(5) for more about ``json`` format.
 
+	See also ``--list-output-formats``.
+
 ``-e``
 	Same as ``--output-format=etags``.
 	Enable etags mode, which will create a tag file for use with the Emacs
@@ -1236,6 +1238,9 @@ Listing Options
 	definition.
 	See ctags-optlib(7).
 
+``--list-output-formats``
+    Lists the output formats that can be used in ``--output-format`` option.
+
 ``--list-params[=(<language>|all)]``
 	Lists the parameters for either the specified *<language>* or ``all``
 	languages, and then exits.