Support sam's structural regular expression based command language

For those not familiar with sam(1) more information can be found at

 http://sam.cat-v.org/

For now sam commands can be entered from the vis prompt via :sam <cmd>

A command behaves differently depending on the mode in which it is issued:

 - in visual mode it behaves as if an implicit extract x command
   matching the current selection(s) would be preceding it. That is
   the command is executed once for each selection.

 - in normal mode:

    * if an address for the command was provided it is evaluated starting
      from the current cursor position(s) i.e. dot is set to the current
      cursor position.

    * if no address was supplied to the command then:

       + if multiple cursors exist, the command is executed once for every
         cursor with dot set to the current line of the cursor

       + otherwise if there is only 1 cursor then the command is executed
         with dot set to the whole file

The command syntax was slightly tweaked to accpet more terse commands.

  - When specifiying text or regular expressions the trailing delimiter can
    be elided if the meaning is unambigious.

  - If only an address is provided the print command will be executed.

  - The print command creates a selection matching its range.

  - In text entry \t inserts a literal tab character (sam only recognizes \n).

Hence the sam command ,x/pattern/ can be abbreviated to x/pattern

If a command is successful vis switches to normal mode (and hence removes
any selections), otherwise the editor is kept in visual mode. The print
command "fails" by definition.

1 files changed, 10 insertions, 0 deletions

diff --git a/vis-cmds.c b/vis-cmds.c
index bb90e35..9365d4e 100644
--- a/vis-cmds.c
+++ b/vis-cmds.c
@@ -16,6 +16,7 @@
 #include "text-motions.h"
 #include "text-objects.h"
 #include "util.h"
+#include "sam.h"
 
 enum CmdOpt {          /* option flags for command definitions */
 	CMD_OPT_NONE,  /* no option (default value) */
@@ -91,6 +92,7 @@ static bool cmd_map(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
 static bool cmd_unmap(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
 /* set language specific key bindings */
 static bool cmd_langmap(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+static bool cmd_sam(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
 
 /* command recognized at the ':'-prompt. commands are found using a unique
  * prefix match. that is if a command should be available under an abbreviation
@@ -124,6 +126,7 @@ static const Command cmds[] = {
 	{ { "later"                    }, cmd_earlier_later, CMD_OPT_NONE               },
 	{ { "!",                       }, cmd_filter,        CMD_OPT_NONE               },
 	{ { "|",                       }, cmd_pipe,          CMD_OPT_NONE               },
+	{ { "sam"                      }, cmd_sam,           CMD_OPT_NONE               },
 	{ { NULL,                      }, NULL,              CMD_OPT_NONE               },
 };
 
@@ -1152,6 +1155,13 @@ static bool cmd_unmap(Vis *vis, Filerange *range, enum CmdOpt opt, const char *a
 		return vis_mode_unmap(vis, mode, lhs);
 }
 
+static bool cmd_sam(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	enum SamError err = sam_cmd(vis, argv[1]);
+	if (err != SAM_ERR_OK)
+		vis_info_show(vis, "%s", sam_error(err));
+	return err == SAM_ERR_OK;
+}
+
 static Filepos parse_pos(Win *win, char **cmd) {
 	size_t pos = EPOS;
 	View *view = win->view;