Bram,
I've added the conditional assignment operator to the source code. Granted, we
aren't adding features now and it isn't on the TODO list, but it was simple to
add and it's pretty useful. Please set it on the shelf until we are ready for
it. Thanks!
*** runtime/doc/eval.txt2006/12/11 21:03:57 1.1
--- runtime/doc/eval.txt2006/12/11 21:04:31
***
*** 5633,5638
--- 5633,5648
from the {expr}. If {var-name} didn't exist yet, it
is created.
+ :let {var-name} ?= {expr1}*:let?=*
+ Set internal variable {var-name} to the result of the
+ expression {expr1} only if {var-name} doesn't exist.
+ This statement:
+ let foo ?= bar
+ is equivalent to this:
+ if !exists(foo)
+ let foo = bar
+ endif
+
:let {var-name}[{idx}] = {expr1} *E689*
Set a list item to the result of the expression
{expr1}. {var-name} must refer to a list and {idx}
***
*** 5665,5670
--- 5675,5684
Append {expr1} to the environment variable {env-name}.
If the environment variable didn't exist yet this
works like =.
+ :let ${env-name} ?= {expr1}
+ Set environment variable {env-name} to the result of
+ the expression {expr1} if {env-name} doesn't exist.
+ The type is always String.
:let @{reg-name} = {expr1}*:let-register* *:[EMAIL
PROTECTED]
Write the result of the expression {expr1} in register
*** src/eval.c 2006/12/08 23:24:51 1.1
--- src/eval.c 2006/12/11 20:49:52
***
*** 1717,1724
op[1] = NUL;
if (expr argend)
{
! if (vim_strchr((char_u *)+-., expr[-1]) != NULL)
! op[0] = expr[-1]; /* +=, -= or .= */
}
expr = skipwhite(expr + 1);
--- 1717,1724
op[1] = NUL;
if (expr argend)
{
! if (vim_strchr((char_u *)+-.?, expr[-1]) != NULL)
! op[0] = expr[-1]; /* +=, -=, .= or ?= */
}
expr = skipwhite(expr + 1);
***
*** 1744,1751
* Assign the typevalue tv to the variable or variables at arg_start.
* Handles both var with any type and [var, var; var] with a list type.
* When nextchars is not NULL it points to a string with characters that
! * must appear after the variable(s). Use +, - or . for add, subtract
! * or concatenate.
* Returns OK or FAIL;
*/
static int
--- 1744,1751
* Assign the typevalue tv to the variable or variables at arg_start.
* Handles both var with any type and [var, var; var] with a list type.
* When nextchars is not NULL it points to a string with characters that
! * must appear after the variable(s). Use +, -, . or ? for add,
! * subtract, concatenate or conditional assign.
* Returns OK or FAIL;
*/
static int
***
*** 2125,2131
typval_T *tv;/* value to assign to variable */
int copy; /* copy value from tv */
char_u*endchars; /* valid chars after variable name or NULL */
! char_u*op;/* +, -, . or NULL*/
{
int c1;
char_u*name;
--- 2125,2131
typval_T *tv;/* value to assign to variable */
int copy; /* copy value from tv */
char_u*endchars; /* valid chars after variable name or NULL */
! char_u*op;/* +, -, ., ? or NULL*/
{
int c1;
char_u*name;
***
*** 2158,2171
c1 = name[len];
name[len] = NUL;
p = get_tv_string_chk(tv);
! if (p != NULL op != NULL *op == '.')
{
int mustfree = FALSE;
char_u *s = vim_getenv(name, mustfree);
if (s != NULL)
{
! p = tofree = concat_str(s, p);
if (mustfree)
vim_free(s);
}
--- 2158,2174
c1 = name[len];
name[len] = NUL;
p = get_tv_string_chk(tv);
! if (p != NULL op != NULL (*op == '.' || *op == '?'))
{
int mustfree = FALSE;
char_u *s = vim_getenv(name, mustfree);
if (s != NULL)
{
! if (*op == '?')
! p = NULL;
!
