From 1634b9439b9767fde22cf79d9ddacd9b33d3e0ca Mon Sep 17 00:00:00 2001
From: Laria Carolin Chabowski <laria@laria.me>
Date: Tue, 7 Mar 2023 21:37:37 +0100
Subject: [PATCH] Implement for / loop / [k]each loops

---
 src/CMakeLists.txt            |  4 ++
 src/apfl.h                    |  3 ++
 src/builtins.c                | 61 ++++++++++++++++--------------
 src/context.c                 | 30 +++++++++++++++
 src/functional-tests/each.at  | 45 ++++++++++++++++++++++
 src/functional-tests/for.at   | 46 +++++++++++++++++++++++
 src/functional-tests/keach.at | 55 +++++++++++++++++++++++++++
 src/functional-tests/loop.at  | 25 +++++++++++++
 src/globals.apfl              | 70 ++++++++++++++++++++++++++++++++++-
 9 files changed, 310 insertions(+), 29 deletions(-)
 create mode 100644 src/functional-tests/each.at
 create mode 100644 src/functional-tests/for.at
 create mode 100644 src/functional-tests/keach.at
 create mode 100644 src/functional-tests/loop.at

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index e7575ea..130b2c8 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -98,7 +98,11 @@ functionaltest("len")
 functionaltest("not")
 functionaltest("type")
 functionaltest("if")
+functionaltest("loop")
 functionaltest("while")
+functionaltest("for")
+functionaltest("keach")
+functionaltest("each")
 functionaltest("eq")
 functionaltest("chained-assignments")
 functionaltest("dictionary-assignments")
diff --git a/src/apfl.h b/src/apfl.h
index 9bad5cd..83e0b53 100644
--- a/src/apfl.h
+++ b/src/apfl.h
@@ -715,6 +715,9 @@ void apfl_get_list_member_by_index(apfl_ctx, apfl_stackidx list, size_t index_in
 void apfl_set_list_member_by_index(apfl_ctx, apfl_stackidx list, size_t index_in_list, apfl_stackidx value);
 // Get the length of a string/list/dict. The value stays on the stack,
 size_t apfl_len(apfl_ctx, apfl_stackidx);
+// Iterate over a dict value, which is popped off the stack first. Calls the callback `it` repeatedly for every
+// key-value pair, which will be pushed on to the stack. Iteration stops, if `it` returns false.
+void apfl_iterate_dict(apfl_ctx, apfl_stackidx dict, void *opaque, bool (*it)(apfl_ctx, void *));
 // Get a string view into a APFL_VALUE_STRING value. The value stays on the stack.
 // The returned string view is only guaranteed to be valid, as long as the value is on the stack.
 struct apfl_string_view apfl_get_string(apfl_ctx, apfl_stackidx);
diff --git a/src/builtins.c b/src/builtins.c
index d1607ac..77787cd 100644
--- a/src/builtins.c
+++ b/src/builtins.c
@@ -308,38 +308,18 @@ type(apfl_ctx ctx)
 }
 
 static void
-impl_while(apfl_ctx ctx)
+impl_loop(apfl_ctx ctx)
 {
-    size_t argc = apfl_len(ctx, 0);
-    if (argc != 2) {
-        apfl_raise_const_error(ctx, "while needs 2 functions as arguments");
-    }
-
-    apfl_get_list_member_by_index(ctx, 0, 0);
-    if (apfl_get_type(ctx, -1) != APFL_VALUE_FUNC) {
-        apfl_raise_const_error(ctx, "while needs 2 functions as arguments");
-    }
-    apfl_get_list_member_by_index(ctx, 0, 1);
-    if (apfl_get_type(ctx, -1) != APFL_VALUE_FUNC) {
-        apfl_raise_const_error(ctx, "while needs 2 functions as arguments");
-    }
-
-    apfl_drop(ctx, 0);
-
-    apfl_push_nil(ctx); // Return value in case of no iteration
-
+    ONE_ARG(ctx, "loop");
+    apfl_list_create(ctx, 0);
     for (;;) {
-        apfl_copy(ctx, 0);
-        apfl_list_create(ctx, 0);
+        apfl_copy(ctx, -2);
+        apfl_copy(ctx, -2);
         apfl_call(ctx, -2, -1);
         if (!apfl_is_truthy(ctx, -1)) {
-            break;
+            apfl_push_nil(ctx);
+            return;
         }
-
-        apfl_drop(ctx, -1);
-        apfl_copy(ctx, 1);
-        apfl_list_create(ctx, 0);
-        apfl_call(ctx, -2, -1);
     }
 }
 
@@ -596,6 +576,30 @@ set_func_name(apfl_ctx ctx)
     apfl_set_func_name(ctx, -2, -1);
 }
 
+static bool
+iterate_dict_callback(apfl_ctx ctx, void *opaque)
+{
+    (void)opaque;
+
+    apfl_list_create(ctx, 2);
+    apfl_list_append(ctx, -1, -3);
+    apfl_list_append(ctx, -1, -2);
+    apfl_copy(ctx, -2);
+    apfl_call(ctx, -1, -2);
+
+    return apfl_is_truthy(ctx, -1);
+}
+
+static void
+iterate_dict(apfl_ctx ctx)
+{
+    apfl_get_list_member_by_index(ctx, 0, 0);
+    apfl_get_list_member_by_index(ctx, 0, 1);
+    apfl_drop(ctx, 0);
+    apfl_iterate_dict(ctx, -2, NULL, iterate_dict_callback);
+    apfl_push_nil(ctx);
+}
+
 static void
 add_builtin(apfl_ctx ctx, const char *name, apfl_cfunc func)
 {
@@ -630,7 +634,7 @@ apfl_builtins(apfl_ctx ctx)
     add_builtin(ctx, "not", not);
     add_builtin(ctx, "len", len);
     add_builtin(ctx, "type", type);
-    add_builtin(ctx, "while", impl_while);
+    add_builtin(ctx, "loop", impl_loop);
     add_builtin(ctx, "gc", impl_gc);
     add_builtin(ctx, "backtrace", impl_backtrace);
     add_builtin(ctx, "fopen", impl_fopen);
@@ -642,4 +646,5 @@ apfl_builtins(apfl_ctx ctx)
     add_builtin(ctx, "-serialize-bytecode", serialize_bytecode);
     add_builtin(ctx, "-unserialize-bytecode", unserialize_bytecode);
     add_builtin(ctx, "set-func-name", set_func_name);
+    add_builtin(ctx, "iterate-dict", iterate_dict);
 }
diff --git a/src/context.c b/src/context.c
index 3083c81..0535a2c 100644
--- a/src/context.c
+++ b/src/context.c
@@ -1357,6 +1357,36 @@ apfl_len(apfl_ctx ctx, apfl_stackidx index)
     return 0;
 }
 
+static void
+iterate_dict_inner(apfl_ctx ctx, apfl_stackidx dict_index, void *opaque, bool (*callback)(apfl_ctx, void *))
+{
+    struct apfl_value dict_value = apfl_value_set_cow_flag(apfl_stack_must_pop(ctx, dict_index));
+    if (!apfl_value_add_as_tmproot(&ctx->gc, dict_value)) {
+        apfl_raise_alloc_error(ctx);
+    }
+
+    if (dict_value.type != VALUE_DICT) {
+        apfl_raise_errorfmt(ctx, "Expected dict value, got {value:type}", dict_value);
+    }
+
+    HASHMAP_EACH(&(dict_value.dict->map), it) {
+        struct apfl_value *k = apfl_hashmap_cursor_peek_key(it);
+        apfl_stack_must_push(ctx, *k);
+        struct apfl_value *v = apfl_hashmap_cursor_peek_value(it);
+        apfl_stack_must_push(ctx, *v);
+        if (!callback(ctx, opaque)) {
+            break;
+        }
+    }
+}
+
+void
+apfl_iterate_dict(apfl_ctx ctx, apfl_stackidx dict, void *opaque, bool (*it)(apfl_ctx, void *))
+{
+    size_t tmproots = apfl_gc_tmproots_begin(&ctx->gc);
+    iterate_dict_inner(ctx, dict, opaque, it);
+    apfl_gc_tmproots_restore(&ctx->gc, tmproots);
+}
 static bool
 get_string_view_of_value(struct apfl_string_view *sv, struct apfl_value value)
 {
diff --git a/src/functional-tests/each.at b/src/functional-tests/each.at
new file mode 100644
index 0000000..0d1a523
--- /dev/null
+++ b/src/functional-tests/each.at
@@ -0,0 +1,45 @@
+===== script =====
+l = ['foo 'bar 'baz]
+each l { v ->
+    print v
+}
+each [] { v ->
+    print "???"
+}
+
+d := [
+    'a -> 'foo
+    'b -> 'bar
+    'c -> 'baz
+]
+seen-foo := seen-bar := seen-baz := 0
+seen-someting-else := false
+
+each d {
+'foo ->
+    seen-foo = + 1 seen-foo
+'bar ->
+    seen-bar = + 1 seen-bar
+'baz ->
+    seen-baz = + 1 seen-baz
+_ ->
+    seen-someting-else = true
+}
+
+keach [->] { k v ->
+    print "???"
+}
+
+print 'seen-foo seen-foo
+print 'seen-bar seen-bar
+print 'seen-baz seen-baz
+print 'seen-someting-else seen-someting-else
+
+===== output =====
+foo
+bar
+baz
+seen-foo 1
+seen-bar 1
+seen-baz 1
+seen-someting-else false
diff --git a/src/functional-tests/for.at b/src/functional-tests/for.at
new file mode 100644
index 0000000..b265483
--- /dev/null
+++ b/src/functional-tests/for.at
@@ -0,0 +1,46 @@
+===== script =====
+for 10 print
+print "---"
+for 2 10 print
+print "---"
+for 10 0 print
+print "---"
+for 20 5 44 print
+
+===== output =====
+0
+1
+2
+3
+4
+5
+6
+7
+8
+9
+---
+2
+3
+4
+5
+6
+7
+8
+9
+---
+10
+9
+8
+7
+6
+5
+4
+3
+2
+1
+---
+20
+25
+30
+35
+40
diff --git a/src/functional-tests/keach.at b/src/functional-tests/keach.at
new file mode 100644
index 0000000..41105ab
--- /dev/null
+++ b/src/functional-tests/keach.at
@@ -0,0 +1,55 @@
+===== script =====
+l = ['foo 'bar 'baz]
+keach l { k v ->
+    print k v
+}
+keach [] { k v ->
+    print "???"
+}
+
+d := [
+    'a -> 'foo
+    'b -> 'bar
+    'c -> 'baz
+]
+seen-a := seen-b := seen-c := 0
+seen-someting-else := false
+a-ok := b-ok := c-ok := false
+
+keach d {
+'a v ->
+    seen-a = + seen-a 1
+    a-ok = == v 'foo
+'b v ->
+    seen-b = + seen-b 1
+    b-ok = == v 'bar
+'c v ->
+    seen-c = + seen-c 1
+    c-ok = == v 'baz
+_ _ ->
+    seen-someting-else = true
+}
+
+keach [->] { k v ->
+    print "???"
+}
+
+print 'seen-a seen-a
+print 'a-ok a-ok
+print 'seen-b seen-b
+print 'b-ok b-ok
+print 'seen-c seen-c
+print 'c-ok c-ok
+print 'seen-someting-else seen-someting-else
+
+===== output =====
+0 foo
+1 bar
+2 baz
+seen-a 1
+a-ok true
+seen-b 1
+b-ok true
+seen-c 1
+c-ok true
+seen-someting-else false
diff --git a/src/functional-tests/loop.at b/src/functional-tests/loop.at
new file mode 100644
index 0000000..3b65bad
--- /dev/null
+++ b/src/functional-tests/loop.at
@@ -0,0 +1,25 @@
+===== script =====
+loop {
+    print "foo"
+    false
+}
+
+i := 0
+loop {
+    i = + i 1
+    print i
+    < i 10
+}
+
+===== output =====
+foo
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10
diff --git a/src/globals.apfl b/src/globals.apfl
index 079a68e..94b28a4 100644
--- a/src/globals.apfl
+++ b/src/globals.apfl
@@ -17,7 +17,7 @@
     not                   := builtins.not
     len                   := builtins.len
     type                  := builtins.type
-    while                 := builtins.while
+    loop                  := builtins.loop
     gc                    := builtins.gc
     backtrace             := builtins.backtrace
     fopen                 := builtins.fopen
@@ -33,6 +33,38 @@
         builtins.set-func-name f name
     }
 
+    while := { cond body ->
+        res := nil
+        loop {
+            if (cond) {
+                res = (body)
+                true
+            } {
+                false
+            }
+        }
+        res
+    }
+
+    for := {
+    end body ->
+        for 0 end body
+    start end body ->
+        if (> start end) {
+            for start -1 end body
+        } {
+            for start 1 end body
+        }
+    start step end body ->
+        end-not-reached := if (> step 0) {{ < start end }} {{ > start end }}
+        out := nil
+        while end-not-reached {
+            out = body start
+            start = + start step
+        }
+        out
+    }
+
     & := { ~strings ->
         join "" strings
     }
@@ -58,6 +90,37 @@
     !>= := -named '!>= (compose not >=)
     !<= := -named '!<= (compose not <=)
 
+    has := {
+    pred cmp y ->
+        { x ->
+            cmp (pred x) y
+        }
+    pred y ->
+        has pred == y
+    }
+
+    keach := {
+    d?(has type 'dict) body ->
+        out := nil
+        builtins.iterate-dict d { k v ->
+            out = body k v
+            true
+        }
+        out
+    l?(has type 'list) body ->
+        out := nil
+        for (len l) { i ->
+            out = body i l@i
+        }
+        out
+    }
+
+    each := { container body ->
+        keach container { _ v ->
+            body v
+        }
+    }
+
     # Dictionary of exported functions
     [
         'if -> if
@@ -78,7 +141,9 @@
         'not -> not
         'len -> len
         'type -> type
+        'loop -> loop
         'while -> while
+        'for -> for
         'gc -> gc
         'backtrace -> backtrace
         'fopen -> fopen
@@ -92,10 +157,13 @@
         '& -> &
         'partial -> partial
         'compose -> compose
+        'has -> has
         '!= -> !=
         '!> -> !>
         '!< -> !<
         '!>= -> !>=
         '!<= -> !<=
+        'keach -> keach
+        'each -> each
     ]
 }