Fix locals with smart combinator macros, document that locals work with macros now

basis/locals/locals-docs.factor

@@ -101,15 +101,27 @@ $nl
 ARTICLE: "locals-limitations" "Limitations of locals"
 "The first limitation is that the " { $link >r } " and " { $link r> } " words may not be used together with locals. Instead, use the " { $link dip } " combinator."
 $nl
-"Another limitation is that closure conversion does not descend into arrays, hashtables or other types of literals. For example, the following does not work:"
+"Another limitation concerns combinators implemented as macros. Locals can only be used with such combinators if the input array immediately precedes the combinator call. For example, the following will work:"
 { $code
-    ":: bad-cond-usage ( a -- ... )"
+    ":: good-cond-usage ( a -- ... )"
     "    {"
     "        { [ a 0 < ] [ ... ] }"
     "        { [ a 0 > ] [ ... ] }"
     "        { [ a 0 = ] [ ... ] }"
     "    } cond ;"
-} ;
+}
+"But not the following:"
+{ $code
+    ": my-cond ( alist -- ) cond ; inline"
+    ""
+    ":: bad-cond-usage ( a -- ... )"
+    "    {"
+    "        { [ a 0 < ] [ ... ] }"
+    "        { [ a 0 > ] [ ... ] }"
+    "        { [ a 0 = ] [ ... ] }"
+    "    } my-cond ;"
+}
+"The reason is that locals are rewritten into stack code at parse time, whereas macro expansion is performed later during compile time. To circumvent this problem, the " { $vocab-link "macros.expander" } " vocabulary is used to rewrite simple macro usages prior to local transformation, however "{ $vocab-link "macros.expander" } " does not deal with more complicated cases where the literal inputs to the macro do not immediately precede the macro call in the source." ;
 
 ARTICLE: "locals" "Local variables and lexical closures"
 "The " { $vocab-link "locals" } " vocabulary implements lexical scope with full closures, both downward and upward. Mutable bindings are supported, including assignment to bindings in outer scope."

basis/locals/locals-tests.factor

@@ -1,6 +1,7 @@
 USING: locals math sequences tools.test hashtables words kernel
 namespaces arrays strings prettyprint io.streams.string parser
-accessors generic eval ;
+accessors generic eval combinators combinators.short-circuit
+combinators.short-circuit.smart ;
 IN: locals.tests
 
 :: foo ( a b -- a a ) a a ;
@@ -276,3 +277,42 @@ M:: sequence method-with-locals ( a -- y ) a reverse ;
     [ \ sequence \ method-with-locals method see ] with-string-writer
     method-definition =
 ] unit-test
+
+:: cond-test ( a b -- c )
+    {
+        { [ a b < ] [ 3 ] }
+        { [ a b = ] [ 4 ] }
+        { [ a b > ] [ 5 ] }
+    } cond ;
+
+[ 3 ] [ 1 2 cond-test ] unit-test
+[ 4 ] [ 2 2 cond-test ] unit-test
+[ 5 ] [ 3 2 cond-test ] unit-test
+
+:: 0&&-test ( a -- ? )
+    { [ a integer? ] [ a even? ] [ a 10 > ] } 0&& ;
+
+[ f ] [ 1.5 0&&-test ] unit-test
+[ f ] [ 3 0&&-test ] unit-test
+[ f ] [ 8 0&&-test ] unit-test
+[ t ] [ 12 0&&-test ] unit-test
+
+:: &&-test ( a -- ? )
+    { [ a integer? ] [ a even? ] [ a 10 > ] } && ;
+
+[ f ] [ 1.5 &&-test ] unit-test
+[ f ] [ 3 &&-test ] unit-test
+[ f ] [ 8 &&-test ] unit-test
+[ t ] [ 12 &&-test ] unit-test
+
+:: wlet-&&-test ( a -- ? )
+    [wlet | is-integer? [ a integer? ]
+            is-even? [ a even? ]
+            >10? [ a 10 > ] |
+        { [ is-integer? ] [ is-even? ] [ >10? ] } &&
+    ] ;
+
+! [ f ] [ 1.5 wlet-&&-test ] unit-test
+! [ f ] [ 3 wlet-&&-test ] unit-test
+! [ f ] [ 8 wlet-&&-test ] unit-test
+! [ t ] [ 12 wlet-&&-test ] unit-test

basis/locals/locals.factor

@@ -5,7 +5,8 @@ parser words quotations debugger macros arrays macros splitting
 combinators prettyprint.backend definitions prettyprint
 hashtables prettyprint.sections sets sequences.private effects
 effects.parser generic generic.parser compiler.units accessors
-locals.backend memoize macros.expander lexer ;
+locals.backend memoize macros.expander lexer
+stack-checker.known-words ;
 IN: locals
 
 ! Inspired by
@@ -42,7 +43,9 @@ PREDICATE: local < word "local?" word-prop ;
 
 : <local> ( name -- word )
     #! Create a local variable identifier
-    f <word> dup t "local?" set-word-prop ;
+    f <word>
+    dup t "local?" set-word-prop
+    dup { } { object } define-primitive ;
 
 PREDICATE: local-word < word "local-word?" word-prop ;
 
@@ -52,15 +55,20 @@ PREDICATE: local-word < word "local-word?" word-prop ;
 PREDICATE: local-reader < word "local-reader?" word-prop ;
 
 : <local-reader> ( name -- word )
-    f <word> dup t "local-reader?" set-word-prop ;
+    f <word>
+    dup t "local-reader?" set-word-prop
+    dup { } { object } define-primitive ;
 
 PREDICATE: local-writer < word "local-writer?" word-prop ;
 
 : <local-writer> ( reader -- word )
-    dup name>> "!" append f <word>
-    [ t "local-writer?" set-word-prop ] keep
-    [ "local-writer" set-word-prop ] 2keep
-    [ swap "local-reader" set-word-prop ] keep ;
+    dup name>> "!" append f <word> {
+        [ nip { object } { } define-primitive ]
+        [ nip t "local-writer?" set-word-prop ]
+        [ swap "local-reader" set-word-prop ]
+        [ "local-writer" set-word-prop ]
+        [ nip ]
+    } 2cleave ;
 
 TUPLE: quote local ;