metaclass instances

7 files changed, 74 insertions, 40 deletions

diff --git a/bos-base.sh b/bos-base.sh
index d964177..3e97b78 100644
--- a/bos-base.sh
+++ b/bos-base.sh
@@ -3,11 +3,12 @@
 function bos/base/new-into() {
     local class _; bos-object/unpack-self-into class _ "$self"
     local -n new_into_result="$1"; shift
-    local metaclass_ref; bos-namespaces/store-scalar-for-into metaclass_ref meta "$class"
-    local -n metaclass_object="$metaclass_ref"
+    local new_into_metaclass_instance; bos-meta/metaclass-instance-for-class-into new_into_metaclass_instance "$class"
 
     local new_object
-    $metaclass_object create-object-into new_object "$class" "$@"
+    $new_into_metaclass_instance create-object-into new_object "$class" "$@"
 
     new_into_result="$new_object"
+
+    return 0
 }
diff --git a/bos-dispatch.sh b/bos-dispatch.sh
index 8306378..d6bc463 100644
--- a/bos-dispatch.sh
+++ b/bos-dispatch.sh
@@ -33,10 +33,8 @@ function bos-dispatch/invoke() {
         return $?
     fi
 
-    local metaclass_ref
-    bos-namespaces/store-scalar-for-into metaclass_ref meta "$class"
-    local -n metaclass_object="$metaclass_ref"
+    local metaclass_instance; bos-meta/metaclass-instance-for-class-into metaclass_instance "$class"
 
-    $metaclass_object invoke "$class" "$self_id" "$method" "$@"
+    $metaclass_instance invoke "$class" "$self_id" "$method" "$@"
     return $?
 }
diff --git a/bos-meta-class.sh b/bos-meta-class.sh
index 9bfdd0a..1fedb45 100644
--- a/bos-meta-class.sh
+++ b/bos-meta-class.sh
@@ -1,9 +1,5 @@
 #!bash
 
-# this encoding must match bos-namespaces/encode-into
-bos_5fbos_2fmeta_2fclass_5fmeta="bos-dipatch/invoke bos/meta/class 0"
-declare -a bos_5fbos_2fmeta_2fclass_5fmro=( "bos/meta/class" )
-
 # these are instance methods of the base metaclass
 
 function bos/meta/class/isa-for-into() {
@@ -152,3 +148,15 @@ function bos/meta/class/create-object-into() {
 
     return 0
 }
+
+function bos/meta/class() {
+    bos-dispatch/invoke bos/meta/class 0 "$@"
+}
+
+declare bos_meta_class_meta_class_instance
+bos/meta/class/create-object-into bos_meta_class_meta_class_instance bos/meta/class
+bos-meta/set-metaclass-instance-for bos/meta/class "$bos_meta_class_meta_class_instance"
+
+$bos_meta_class_meta_class_instance make-mro-for bos/meta/class
+
+unset bos_meta_class_meta_class_instance
diff --git a/bos-meta.sh b/bos-meta.sh
new file mode 100644
index 0000000..6932095
--- /dev/null
+++ b/bos-meta.sh
@@ -0,0 +1,17 @@
+#!bash
+
+declare -A bos_meta_metaclass_instance_for_class
+
+function bos-meta/set-metaclass-instance-for() {
+    bos_meta_metaclass_instance_for_class["$1"]="$2"
+
+    return 0
+}
+
+function bos-meta/metaclass-instance-for-class-into() {
+    local -n bos_meta_metaclass_instance_result="$1"
+
+    bos_meta_metaclass_instance_result="${bos_meta_metaclass_instance_for_class[$2]}"
+
+    return 0
+}
diff --git a/bos-sugar.sh b/bos-sugar.sh
index 8f3a810..152f5d8 100644
--- a/bos-sugar.sh
+++ b/bos-sugar.sh
@@ -31,31 +31,34 @@ function bos-sugar/declare-block() {
 
 # ----
 
-function bos-sugar/set-metaclass-for() {
-    local class="$1"
-    local metaclass_ref; bos-namespaces/store-scalar-for-into metaclass_ref meta "$class"
-    local -n metaclass_object="$metaclass_ref"
-    metaclass_object='bos-dispatch/invoke bos/meta/class 0'
+function bos-sugar/declare-helpers() {
+    function extends() {
+        local fq_class; bos-namespaces/current-namespace-into fq_class
+        local metaclass_instance; bos-meta/metaclass-instance-for-class-into metaclass_instance "$fq_class"
+        $metaclass_instance set-superclasses-for "$fq_class" "$@"
+    }
+}
+
+function bos-sugar/remove-helpers() {
+    unset extends
 }
 
 function bos-sugar/class-open() {
-    if [[ "${#*}" -ne 1 ]]; then
-        >&2 echo "'class \$class_name; do …; done', not 'class $*'"
+    if [[ "${#*}" -lt 1 || "${#*}" -gt 2 ]]; then
+        >&2 echo "'class \$class_name [\$metaclass]; do …; done', not 'class $*'"
         return 1
     fi
+    local class="$1"
+    local metaclass="${2:-bos/meta/class}"
 
-    function extends() {
-        local fq_class; bos-namespaces/current-namespace-into fq_class
-        local metaclass_ref; bos-namespaces/store-scalar-for-into metaclass_ref meta "$fq_class"
-        local -n metaclass_object="$metaclass_ref"
-        $metaclass_object set-superclasses-for "$fq_class" "$@"
-    }
+    bos-sugar/declare-helpers
 
-    local class="$1"
     bos-namespaces/namespace-open "$1"
 
     local fq_class; bos-namespaces/current-namespace-into fq_class
-    bos-sugar/set-metaclass-for "$fq_class"
+    local class_open_metaclass_instance; $metaclass new-into class_open_metaclass_instance
+
+    bos-meta/set-metaclass-instance-for "$fq_class" "$class_open_metaclass_instance"
 
     return 0
 }
@@ -64,16 +67,18 @@ function bos-sugar/class-close() {
     local class="$1";
 
     local fq_class; bos-namespaces/current-namespace-into fq_class
-    local metaclass_ref; bos-namespaces/store-scalar-for-into metaclass_ref meta "$fq_class"
-    local -n metaclass_object="$metaclass_ref"
 
     bos-namespaces/namespace-close
 
-    $metaclass_object make-mro-for "$fq_class"
+    local class_close_metaclass_instance; bos-meta/metaclass-instance-for-class-into class_close_metaclass_instance "$fq_class"
+
+    $class_close_metaclass_instance make-mro-for "$fq_class"
 
     # TODO this should probably be done by the metaclass?
     eval "function $fq_class { bos-dispatch/invoke \"$fq_class\" 0 \"\$@\"; }"
 
+    bos-sugar/remove-helpers
+
     return 0
 }
 
diff --git a/meta-stuff.rst.txt b/meta-stuff.rst.txt
index 46fabf5..ea5a074 100644
--- a/meta-stuff.rst.txt
+++ b/meta-stuff.rst.txt
@@ -10,10 +10,15 @@ done bits
 
 * ``bos/mop/base`` + ``bos/mop/inheritance`` become ``bos/meta/class``
 
-next bits…
+  * store class→metaclass association somewhere (global dictionary,
+    probably)
 
-* formalise that ``bos-dispatch/invoke $class 0 $method $args`` is a
-  class method invocation
+  - when creating a class, create a metaclass instance and store it
+  - the store must be pre-populated with metaclass instances for:
+
+    + ``bos/meta/class`` → ``bos-dispatch/invoke bos/meta/class 1``
+
+next bits…
 
 * add ``bos/meta/attribute``
 
@@ -32,13 +37,12 @@ next bits…
   - ``add-attribute``
   - add class, mro, as attributes to the metaclass
 
-* store class→metaclass association somewhere (global dictionary,
-  probably)
+* pre-populated metaclass instances for:
 
-  - when creating a class, create a metaclass instance and store it
-  - the store must be pre-populated with metaclass instances for:
+  - ``bos/meta/class`` → ``bos-dispatch/invoke bos/meta/class 1``
+  - ``bos/meta/attribute`` → ``bos-dispatch/invoke bos/meta/class 2``
 
-    + ``bos/meta/class`` → ``bos-dispatch/invoke bos/meta/class 1``
-    + ``bos/meta/attribute`` → ``bos-dispatch/invoke bos/meta/class 2``
+  and those instances' attributes must be manually stored
 
-    and those instances' attributes must be manually stored
+* formalise that ``bos-dispatch/invoke $class 0 $method $args`` is a
+  class method invocation
diff --git a/t/testlib.sh b/t/testlib.sh
index af5eed2..edbd973 100644
--- a/t/testlib.sh
+++ b/t/testlib.sh
@@ -2,11 +2,12 @@
 
 PS4='[${#FUNCNAME[*]}] ${BASH_SOURCE[0]}:${LINENO} (${FUNCNAME[0]}) +'
 
+. bos-dispatch.sh
 . bos-namespaces.sh
 . bos-object-id.sh
 . bos-base.sh
+. bos-meta.sh
 . bos-meta-class.sh
-. bos-dispatch.sh
 . bos-sugar.sh
 
 . minitap.sh