Hi Bram and mattn,
2016/7/3 Sun 6:27:36 UTC+9 Bram Moolenaar wrote:
> Ken Takata wrote:
>
> > 2016/5/27 Fri 22:38:34 UTC+9 Ken Takata wrote:
> > > Hi mattn,
> > >
> > > 2016/4/18 Mon 0:30:19 UTC+9 mattn wrote:
> > > > Hi, Bram and list.
> > > >
> > > > Updated lambda patch to be applied for latest code.
> > > >
> > > > https://gist.github.com/mattn/5bc8ded21e1033c9c0ea8cd5ecbbce11
> > > >
> > > > This include examples for timer on help file. I'm thinking lambda()
> > > > have cooperative to work with job/timer/channel.
> > > >
> > > > So I hope to add this into vim8. How do you think?
> > > >
> > > > Thanks to k-takata, haya14busa, and all of members on vim-jp.
> > >
> > > I have tested the lambda patch with the latest Vim and I found two
> > > problems.
> > >
> > > 1. garbagecollect_for_testing() was renamed.
> > > 2. Test_lambda_with_timer() fails on Cygwin. It seems that we need
> > > margins
> > > as we do in test_timers.vim.
> > >
> > > Please check attached patch.
> > >
> > > I hope that the lambda patch will be merged in Vim 8.0.
> > > This makes filter(), map() and sort() easy to use.
> > > It also works nicely with job/channel/timer features.
> >
> > I have merged my patch into your patch, and also fixed that the function
> > declaration was not sorted in alphabetical order.
> > Please check the attached patch.
>
> I have mixed feelings about this implementation. This needs more
> thoughts and discussion.
>
>
> One of the problems with the current use of a string for an expression,
> as it's passed to map(), filter(), etc., is that this is a string, which
> requires taking care of quotes.
>
> Using lambda() for that doesn't have an advantage, it's only longer:
>
> :call map(mylist, '"> " . v:val . " <"')
> :call map(mylist, lambda('"> " . v:val . " <"'))
>
> Perhaps we can define the lambda not as a function call, but as an
> operator. Then it will be parsed differently and we don't need to put
> the expression in quotes. We do want to be able to define it inline, as
> a function argument. We do need something around it, so that it's clear
> where the end is. Using {} would work, it's similar to a statement
> block in most languages.
>
> We would also like to specify arguments. We could separate the
> arguments from the statements with a "gives" symbol. That could be ->.
> This avoid the strange use of v:val and v:key to pass values to the
> expression, like map() does.
>
> call Func(arg, lambda{v -> return v * 3.12})
>
> That way we can do this:
> call map(mylist, lambda{v -> return "> " . v . " <"})
>
> In most cases only one statement is needed, but having a few more should
> be possible. Using | to separate statements hopefully works:
>
> call Func(arg, lambda{ v -> if v < 0 | return v * 3.12 | else | return
> v * -3.12 | endif})
>
> Something like that. If it gets too long it's better to just define a
> function.
>
>
> The implementation also takes items from the context, thus creating a
> closure. I don't think that should be specific to a lambda, defining a
> function inside another function should be able to do the same thing.
> After all, a lambda is just a short way of defining a nameless function.
>
> In the implementation it seems the dictionary storing the function-local
> variables is kept for a very long time. This relies on the garbage
> collector. It's better to use reference counting to be able to free the
> dictionary as soon as it's unused.
>
> Also, the lambda always keeps the function-local variable dict, even
> when it's not actually used. That makes lambdas a expensive.
> It would be better to explicitly state the lambda is using its context.
> Then we can also do that with ":function", so that we are not forced to
> use a lambda if we want a closure.
>
> However, I'm not sure we need this. It is possible to bind a function
> to a dictionary, which can then contain anything that's to be kept
> between calls.
>
>
> Being able to pass a function to map(), sort(), etc. is good. However,
> it looks like in the implementation only VAR_FUNC is supported, not
> VAR_PARTIAL. It should be both.
It seems that it's better to divide the lambda patch into several patches.
E.g.:
1. lambda expression
2. closure
3. enable to pass a function to filter() and map()
I wrote a patch for #3. I slightly changed the specification so that a
function has both key and value as arguments. I also added some tests for
filter() and map(). Please check.
Regards,
Ken Takata
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# HG changeset patch
# Parent e8cf557dd9c2d7d7c9820048ae37d614e2b8d312
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -3521,11 +3521,12 @@ filewritable({file}) *filewritable()
directory, and we can write to it, the result is 2.
-filter({expr}, {string}) *filter()*
- {expr} must be a |List| or a |Dictionary|.
- For each item in {expr} evaluate {string} and when the result
+filter({expr1}, {expr2}) *filter()*
+ {expr1} must be a |List| or a |Dictionary|.
+ For each item in {expr1} evaluate {expr2} and when the result
is zero remove the item from the |List| or |Dictionary|.
- Inside {string} |v:val| has the value of the current item.
+ {expr2} must be a |string| or |Funcref|. If it is a |string|,
+ inside {expr2} |v:val| has the value of the current item.
For a |Dictionary| |v:key| has the key of the current item.
Examples: >
:call filter(mylist, 'v:val !~ "OLD"')
@@ -3535,17 +3536,22 @@ filter({expr}, {string}) *filter()*
:call filter(var, 0)
< Removes all the items, thus clears the |List| or |Dictionary|.
- Note that {string} is the result of expression and is then
+ Note that {expr2} is the result of expression and is then
used as an expression again. Often it is good to use a
|literal-string| to avoid having to double backslashes.
+ If {expr2} is a |Funcref|, the first argument has the key or
+ the index of the current item. The second argument has the
+ value of the current item. The function should return TRUE
+ if the item should be kept.
+
The operation is done in-place. If you want a |List| or
|Dictionary| to remain unmodified make a copy first: >
:let l = filter(copy(mylist), 'v:val =~ "KEEP"')
-< Returns {expr}, the |List| or |Dictionary| that was filtered.
- When an error is encountered while evaluating {string} no
- further items in {expr} are processed.
+< Returns {expr1}, the |List| or |Dictionary| that was filtered.
+ When an error is encountered while evaluating {expr2} no
+ further items in {expr1} are processed.
finddir({name}[, {path}[, {count}]]) *finddir()*
@@ -5036,29 +5042,35 @@ luaeval({expr}[, {expr}]) *luaeval()
See |lua-luaeval| for more details.
{only available when compiled with the |+lua| feature}
-map({expr}, {string}) *map()*
- {expr} must be a |List| or a |Dictionary|.
- Replace each item in {expr} with the result of evaluating
- {string}.
- Inside {string} |v:val| has the value of the current item.
+map({expr1}, {expr2}) *map()*
+ {expr1} must be a |List| or a |Dictionary|.
+ Replace each item in {expr1} with the result of evaluating
+ {expr2}.
+ {expr2} must be a |string| or |Funcref|. If it is a |string|,
+ inside {expr2} |v:val| has the value of the current item.
For a |Dictionary| |v:key| has the key of the current item
and for a |List| |v:key| has the index of the current item.
Example: >
:call map(mylist, '"> " . v:val . " <"')
< This puts "> " before and " <" after each item in "mylist".
- Note that {string} is the result of an expression and is then
+ Note that {expr2} is the result of an expression and is then
used as an expression again. Often it is good to use a
|literal-string| to avoid having to double backslashes. You
still have to double ' quotes
+ If {expr2} is a |Funcref|, the first argument has the key or
+ the index of the current item. The second argument has the
+ value of the current item. The function should return a
+ value to replace the item with it.
+
The operation is done in-place. If you want a |List| or
|Dictionary| to remain unmodified make a copy first: >
:let tlist = map(copy(mylist), ' v:val . "\t"')
-< Returns {expr}, the |List| or |Dictionary| that was filtered.
- When an error is encountered while evaluating {string} no
- further items in {expr} are processed.
+< Returns {expr1}, the |List| or |Dictionary| that was filtered.
+ When an error is encountered while evaluating {expr2} no
+ further items in {expr1} are processed.
maparg({name}[, {mode} [, {abbr} [, {dict}]]]) *maparg()*
diff --git a/src/Makefile b/src/Makefile
--- a/src/Makefile
+++ b/src/Makefile
@@ -2031,6 +2031,7 @@ test_arglist \
test_farsi \
test_feedkeys \
test_file_perm \
+ test_filter_map \
test_fnamemodify \
test_glob2regpat \
test_goto \
diff --git a/src/eval.c b/src/eval.c
--- a/src/eval.c
+++ b/src/eval.c
@@ -11852,7 +11852,7 @@ findfilendir(
}
static void filter_map(typval_T *argvars, typval_T *rettv, int map);
-static int filter_map_one(typval_T *tv, char_u *expr, int map, int *remp);
+static int filter_map_one(typval_T *tv, typval_T *expr, int map, int *remp);
/*
* Implementation of map() and filter().
@@ -11860,8 +11860,7 @@ static int filter_map_one(typval_T *tv,
static void
filter_map(typval_T *argvars, typval_T *rettv, int map)
{
- char_u buf[NUMBUFLEN];
- char_u *expr;
+ typval_T *expr;
listitem_T *li, *nli;
list_T *l = NULL;
dictitem_T *di;
@@ -11896,14 +11895,13 @@ filter_map(typval_T *argvars, typval_T *
return;
}
- expr = get_tv_string_buf_chk(&argvars[1], buf);
+ expr = &argvars[1];
/* On type errors, the preceding call has already displayed an error
* message. Avoid a misleading error message for an empty string that
* was not passed as argument. */
- if (expr != NULL)
+ if (expr->v_type != VAR_UNKNOWN)
{
prepare_vimvar(VV_VAL, &save_val);
- expr = skipwhite(expr);
/* We reset "did_emsg" to be able to detect whether an error
* occurred during evaluation of the expression. */
@@ -11975,21 +11973,44 @@ filter_map(typval_T *argvars, typval_T *
}
static int
-filter_map_one(typval_T *tv, char_u *expr, int map, int *remp)
+filter_map_one(typval_T *tv, typval_T *expr, int map, int *remp)
{
typval_T rettv;
+ typval_T argv[3];
char_u *s;
int retval = FAIL;
+ int dummy;
copy_tv(tv, &vimvars[VV_VAL].vv_tv);
- s = expr;
- if (eval1(&s, &rettv, TRUE) == FAIL)
- goto theend;
- if (*s != NUL) /* check for trailing chars after expr */
- {
- EMSG2(_(e_invexpr2), s);
- clear_tv(&rettv);
- goto theend;
+ argv[0] = vimvars[VV_KEY].vv_tv;
+ argv[1] = vimvars[VV_VAL].vv_tv;
+ s = expr->vval.v_string;
+ if (expr->v_type == VAR_FUNC)
+ {
+ if (call_func(s, (int)STRLEN(s),
+ &rettv, 2, argv, 0L, 0L, &dummy, TRUE, NULL, NULL) == FALSE)
+ goto theend;
+ }
+ else if (expr->v_type == VAR_PARTIAL)
+ {
+ partial_T *partial = expr->vval.v_partial;
+
+ s = partial->pt_name;
+ if (call_func(s, (int)STRLEN(s),
+ &rettv, 2, argv, 0L, 0L, &dummy, TRUE, partial, NULL)
+ == FALSE)
+ goto theend;
+ }
+ else
+ {
+ s = skipwhite(s);
+ if (eval1(&s, &rettv, TRUE) == FAIL)
+ goto theend;
+ if (*s != NUL) /* check for trailing chars after expr */
+ {
+ EMSG2(_(e_invexpr2), s);
+ goto theend;
+ }
}
if (map)
{
diff --git a/src/testdir/test_alot.vim b/src/testdir/test_alot.vim
--- a/src/testdir/test_alot.vim
+++ b/src/testdir/test_alot.vim
@@ -12,6 +12,7 @@ source test_expand_dllpath.vim
source test_feedkeys.vim
source test_fnamemodify.vim
source test_file_perm.vim
+source test_filter_map.vim
source test_glob2regpat.vim
source test_goto.vim
source test_help_tagjump.vim
diff --git a/src/testdir/test_filter_map.vim b/src/testdir/test_filter_map.vim
new file mode 100644
--- /dev/null
+++ b/src/testdir/test_filter_map.vim
@@ -0,0 +1,77 @@
+" Test filter() and map()
+
+" list with expression string
+func Test_filter_map_list_expr_string()
+ " filter()
+ call assert_equal([2, 3, 4], filter([1, 2, 3, 4], 'v:val > 1'))
+ call assert_equal([3, 4], filter([1, 2, 3, 4], 'v:key > 1'))
+
+ " map()
+ call assert_equal([2, 4, 6, 8], map([1, 2, 3, 4], 'v:val * 2'))
+ call assert_equal([0, 2, 4, 6], map([1, 2, 3, 4], 'v:key * 2'))
+endfunc
+
+" dict with expression string
+func Test_filter_map_dict_expr_string()
+ let dict = {"foo": 1, "bar": 2, "baz": 3}
+
+ " filter()
+ call assert_equal({"bar": 2, "baz": 3}, filter(copy(dict), 'v:val > 1'))
+ call assert_equal({"foo": 1, "baz": 3}, filter(copy(dict), 'v:key > "bar"'))
+
+ " map()
+ call assert_equal({"foo": 2, "bar": 4, "baz": 6}, map(copy(dict), 'v:val * 2'))
+ call assert_equal({"foo": "f", "bar": "b", "baz": "b"}, map(copy(dict), 'v:key[0]'))
+endfunc
+
+" list with funcref
+func Test_filter_map_list_expr_funcref()
+ " filter()
+ func! s:filter1(index, val) abort
+ return a:val > 1
+ endfunc
+ call assert_equal([2, 3, 4], filter([1, 2, 3, 4], function('s:filter1')))
+
+ func! s:filter2(index, val) abort
+ return a:index > 1
+ endfunc
+ call assert_equal([3, 4], filter([1, 2, 3, 4], function('s:filter2')))
+
+ " map()
+ func! s:filter3(index, val) abort
+ return a:val * 2
+ endfunc
+ call assert_equal([2, 4, 6, 8], map([1, 2, 3, 4], function('s:filter3')))
+
+ func! s:filter4(index, val) abort
+ return a:index * 2
+ endfunc
+ call assert_equal([0, 2, 4, 6], map([1, 2, 3, 4], function('s:filter4')))
+endfunc
+
+" dict with funcref
+func Test_filter_map_dict_expr_funcref()
+ let dict = {"foo": 1, "bar": 2, "baz": 3}
+
+ " filter()
+ func! s:filter1(key, val) abort
+ return a:val > 1
+ endfunc
+ call assert_equal({"bar": 2, "baz": 3}, filter(copy(dict), function('s:filter1')))
+
+ func! s:filter2(key, val) abort
+ return a:key > "bar"
+ endfunc
+ call assert_equal({"foo": 1, "baz": 3}, filter(copy(dict), function('s:filter2')))
+
+ " map()
+ func! s:filter3(key, val) abort
+ return a:val * 2
+ endfunc
+ call assert_equal({"foo": 2, "bar": 4, "baz": 6}, map(copy(dict), function('s:filter3')))
+
+ func! s:filter4(key, val) abort
+ return a:key[0]
+ endfunc
+ call assert_equal({"foo": "f", "bar": "b", "baz": "b"}, map(copy(dict), function('s:filter4')))
+endfunc
diff --git a/src/testdir/test_partial.vim b/src/testdir/test_partial.vim
--- a/src/testdir/test_partial.vim
+++ b/src/testdir/test_partial.vim
@@ -14,6 +14,14 @@ func MySort(up, one, two)
return a:one < a:two ? 1 : -1
endfunc
+func MyMap(sub, index, val)
+ return a:val - a:sub
+endfunc
+
+func MyFilter(threshold, index, val)
+ return a:val > a:threshold
+endfunc
+
func Test_partial_args()
let Cb = function('MyFunc', ["foo", "bar"])
@@ -36,6 +44,16 @@ func Test_partial_args()
call assert_equal([1, 2, 3], sort([3, 1, 2], Sort))
let Sort = function('MySort', [0])
call assert_equal([3, 2, 1], sort([3, 1, 2], Sort))
+
+ let Map = function('MyMap', [2])
+ call assert_equal([-1, 0, 1], map([1, 2, 3], Map))
+ let Map = function('MyMap', [3])
+ call assert_equal([-2, -1, 0], map([1, 2, 3], Map))
+
+ let Filter = function('MyFilter', [1])
+ call assert_equal([2, 3], filter([1, 2, 3], Filter))
+ let Filter = function('MyFilter', [2])
+ call assert_equal([3], filter([1, 2, 3], Filter))
endfunc
func MyDictFunc(arg1, arg2) dict
@@ -60,6 +78,9 @@ func Test_partial_dict()
call assert_equal("hello/xxx/yyy", Cb("xxx", "yyy"))
call assert_fails('Cb("fff")', 'E492:')
+ let Cb = function('MyDictFunc', dict)
+ call assert_equal({"foo": "hello/foo/1", "bar": "hello/bar/2"}, map({"foo": 1, "bar": 2}, Cb))
+
let dict = {"tr": function('tr', ['hello', 'h', 'H'])}
call assert_equal("Hello", dict.tr())
endfunc
