[settings] Use a generic setting's own type as its default type

When fetching a named setting using a name that does not explicitly
specify a type, default to using the type stored when the setting was
created, rather than always defaulting to "string".  This allows the
behaviour of user-defined settings to match the behaviour of
predefined settings (which have a sensible default type).

For example:

  set server:ipv4 192.168.0.1
  echo ${server}

will now print "192.168.0.1", rather than trying to print out the raw
IPv4 address bytes as a string.

The downside of this change is that existing tricks for printing
special characters within scripts may require (backwards-compatible)
modification.  For example, the "clear screen" sequence:

  set esc:hex 1b
  set cls ${esc}[2J
  echo ${cls}

will now have to become

  set esc:hex 1b
  set cls ${esc:string}[2J  # Must now explicitly specify ":string"
  echo ${cls}

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/src/include/ipxe/settings.h b/src/include/ipxe/settings.h
index cd446202..a81e5ccf 100644
--- a/src/include/ipxe/settings.h
+++ b/src/include/ipxe/settings.h
@@ -280,7 +280,12 @@ extern int fetchf_setting ( struct settings *settings, struct setting *setting,
 extern int storef_setting ( struct settings *settings,
 			    struct setting *setting,
 			    const char *value );
-extern int storef_named_setting ( const char *name, const char *value );
+extern int store_named_setting ( const char *name,
+				 struct setting_type *default_type,
+				 const void *data, size_t len );
+extern int storef_named_setting ( const char *name,
+				  struct setting_type *default_type,
+				  const char *value );
 extern int fetchf_named_setting ( const char *name, char *name_buf,
 				  size_t name_len, char *value_buf,
 				  size_t value_len );
@@ -366,7 +371,7 @@ static inline int delete_setting ( struct settings *settings,
  * @ret rc		Return status code
  */
 static inline int delete_named_setting ( const char *name ) {
-	return storef_named_setting ( name, NULL );
+	return store_named_setting ( name, NULL, NULL, 0 );
 }
 
 /**