Implement the Sufficiently Simple Syntax macro, some cleanup

main.lua

@@ -1,6 +1,6 @@
 -- bootstrap the compiler
 fennel = require("lib.fennel")
-table.insert(package.loaders, fennel.make_searcher())
+table.insert(package.loaders, fennel.searcher)
 debug.traceback = fennel.traceback
 fv = fennel.view
 pp = function(x) print(fv(x)) end

ssc/init.fnl

@@ -34,7 +34,6 @@
 ; * implement read / write (pointers)
 ; * implement write (locals)
 ; * implement loops
-; * implement custom special forms (macros?)
 ; * implement "getters" (subroutine that runs when referenced by name without an explicit call)
 
 (local Object (require :core.object))
@@ -70,7 +69,7 @@
   (fn [_ iprev] (let [i (if iprev (+ iprev 2) 1)]
                           (when (< i (length l)) (values i (. l i) (. l (+ i 1)))))))
 
-(fn boolop [self left right negbranch]
+(fn boolop [self left right branch]
   (let [compiled-left    (self:compile-expr left)
         push-left        (when (not= (type right) :number) (self:push))
         compiled-compare (if (not push-left) [:cmp right]
@@ -79,11 +78,11 @@
     [:block
       compiled-left
       compiled-compare
-      [negbranch :-false-]
+      [branch :-true-]
-      [:lda 0xffff]
-      [:bra :-finished-]
-    :-false-
       [:lda 0]
+      [:bra :-finished-]
+    :-true-
+      [:lda 0xffff]
     :-finished-
       drop-left]))
 
@@ -124,31 +123,33 @@
                     (where sym (= (type sym) :string) (self:local-offset sym)) [:block [:sec] [:sbc (self:local-offset sym) :s]]
                     _ [:block (self:push) (self:compile-expr val) [:sec] [:sbc 0 :s] (self:drop)])))))
           block))
-    := (lambda [self lhs rhs] (boolop self lhs rhs :bne))
+    := (lambda [self lhs rhs] (boolop self lhs rhs :beq))
-    :not= (lambda [self lhs rhs] (boolop self lhs rhs :beq))
+    :not= (lambda [self lhs rhs] (boolop self lhs rhs :bne))
     :< (lambda [self lhs rhs] (boolop self lhs rhs :bmi))
+    :> (lambda [self lhs rhs] (boolop self rhs lhs :bmi))
     :>= (lambda [self lhs rhs] (boolop self lhs rhs :bpl))
-    :> (lambda [self lhs rhs] (boolop self rhs lhs :bpl))
+    :<= (lambda [self lhs rhs] (boolop self rhs lhs :bpl))
-    :<= (lambda [self lhs rhs] (boolop self rhs lhs :bmi))
     :not (lambda [self bool] (self:compile-expr [:if bool 0 0xffff]))
     :if (lambda [self test iftrue ?iffalse]
-          [:block
+          (lume.concat
-            (self:compile-expr test)
+            [:block
-            [:cmp 0]
+              (self:compile-expr test)
-            [:beq :-elseblock-]
+              [:cmp 0]
-            (self:compile-expr iftrue)
+              [:beq :-elseblock-]
-            (when ?iffalse [:bra :-finished-])
+              (self:compile-expr iftrue)]
-          :-elseblock-
+              (when ?iffalse [[:bra :-finished-]])
-            (when ?iffalse (self:compile-expr ?iffalse))
+            [:-elseblock-]
-          :-finished-])
+              (when ?iffalse [(self:compile-expr ?iffalse)])
+            [:-finished-]))
     :fn (lambda [self name args ...]
           (assert (= (length self.locals) 0))
           (set self.locals (lume.concat args [[:tmp]]))
           (tset self.functions name {:arity (length args) : args :org self.org})
-          ; todo: maybe handle mutually recursive functions?
+          ; todo: maybe handle mutually recursive functions? (compile-expr only has access to currently-defined functions)
-          (self.org:append name (self:compile-expr (lume.push [:do ...] [:asm [:rts]])))
+          (self.org:append name (self:compile-expr (lume.concat [:do ...] [[:asm [:rts]]])))
           (assert (= (length self.locals) (+ (length args) 1)))
           (set self.locals []))
+    :form (lambda [self name func] (tset self.forms name func))
   })
 
 (fn Ssc.local-offset [self symbol]
@@ -169,8 +170,12 @@
         (lume.concat [:block] pre [[:jsr func]] post))
     (where [form & args] (. self.forms form))
       ((. self.forms form) self (table.unpack args))
+    nil [:block]
     _ (error (.. "Unrecognized expression " (fv expr)))))
 
-(pp (: (Ssc) :compile-expr [:let [:x 2 :y 4] [:if [:< :x :y] :x :y]]))
+(fn Ssc.compile [self ...]
+  (for [i 1 (select :# ...)]
+    (self:compile-expr (select i ...)))
+  self)
 
 Ssc

ssc/macros.fnl

@@ -0,0 +1,24 @@
+; Sufficiently Simple Syntax macro
+; This is basically just a quote that converts fennel syntax to Lua tables.
+; Turns symbols into strings and lists into table literals. Table literals can be used to escape into regular fennel.
+; Examples:
+;    (let (x 1 y 2) (+ "x" :y))
+; => [:let [:x 1 :y 2] [:+ :x :y]]
+;    (form mymacro [(fn [ssc] (ssc:compile-expr [:+ 1 2]))])
+; => [:form :mymacro (fn [ssc] (ssc:compile-expr [:+ 1 2]))]
+
+(fn form-to-fnl [form]
+  (if (sym? form)      (tostring form)
+      (sequence? form) (. form 1) ; escape
+      (list? form)     (icollect [_ inner-form (ipairs form)] (form-to-fnl inner-form))
+    form))
+
+(fn sss [...]
+  (let [result `(values)]
+    (for [i 1 (select :# ...)]
+      (table.insert result (form-to-fnl (select i ...))))
+    result))
+
+(fn compile [ssc ...] `(: ,ssc :compile ,(sss ...)))
+
+{: sss : form-to-fnl : compile}

wrap.fnl

@@ -10,6 +10,8 @@
 (local translate (require :core.doc.translate))
 (local files (require :game.files))
 
+(setmetatable _G nil)
+
 (command.add nil {
   "honeylisp:open-project" (fn []
     (core.command_view:enter "Open Project"