From d546c89b00227003c843793bdb32324fad60b260 Mon Sep 17 00:00:00 2001
From: Frank Duncan <frank@kank.net>
Date: Sun, 24 Apr 2016 11:52:14 -0500
Subject: [PATCH] Prims - Implement if, ifelse

---
 src/main/transpile.lisp   | 20 +++++++++++++++++++-
 src/test/simpletests.lisp | 12 ++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/src/main/transpile.lisp b/src/main/transpile.lisp
index 4a6a5a0..9b4b5ee 100644
--- a/src/main/transpile.lisp
+++ b/src/main/transpile.lisp
@@ -1,6 +1,7 @@
 (in-package #:clnl-transpiler)
 
 (defparameter *prims* nil)
+(defparameter *prim-aliases* nil)
 
 (defun prim-name (prim) (getf prim :name))
 (defun prim-type (prim) (getf prim :type))
@@ -8,7 +9,10 @@
 (defun is-reporter (prim) (eql :reporter (getf prim :type)))
 (defun is-command (prim) (eql :command (getf prim :type)))
 
-(defun find-prim (symb) (find symb *prims* :key #'prim-name))
+(defun find-prim (symb)
+ (or
+  (find symb *prims* :key #'prim-name)
+  (find-prim (getf (find symb *prim-aliases* :key #'prim-name) :real-symb))))
 
 ; Let this grow, slowly but surely, eventually taking on calling context, etc.
 ; For now, it's just a
@@ -68,12 +72,19 @@ DESCRIPTION:
 (defun transpile-command-block (block)
  `(lambda () ,@(mapcar #'transpile-command (cdr block))))
 
+; Undoes the previous function :)
+(defun make-command-block-inline (block)
+ (cddr block))
+
 (defmacro defprim (name type func)
  `(push (list :name ,name :type ,type :func ,func) *prims*))
 
 (defmacro defsimpleprim (name type simple-func)
  `(defprim ,name ,type (lambda (&rest args) `(,',simple-func ,@args))))
 
+(defmacro defprim-alias (name real-symb)
+ `(push (list :name ,name :real-symb ,real-symb) *prim-aliases*))
+
 ; We count on the parser to handle arguemnts for us, when collating things.
 
 (defsimpleprim := :reporter cl:equalp)
@@ -89,6 +100,13 @@ DESCRIPTION:
 (defsimpleprim :crt :command clnl-nvm:create-turtles)
 (defsimpleprim :die :command clnl-nvm:die)
 (defsimpleprim :fd :command clnl-nvm:forward)
+(defprim :if :command (lambda (pred a) `(when ,pred ,@(make-command-block-inline a))))
+(defprim :ifelse :command (lambda (pred a b)
+                           `(if ,pred
+                             ,@(make-command-block-inline a)
+                             ,@(make-command-block-inline b))))
+
+(defprim-alias :if-else :ifelse)
 (defsimpleprim :lt :command clnl-nvm:turn-left)
 (defsimpleprim :random-float :reporter clnl-nvm:random-float)
 (defsimpleprim :rt :command clnl-nvm:turn-right)
diff --git a/src/test/simpletests.lisp b/src/test/simpletests.lisp
index 9feaf8d..119e12f 100644
--- a/src/test/simpletests.lisp
+++ b/src/test/simpletests.lisp
@@ -119,3 +119,15 @@
 
 (defsimplecommandtest "lt 2" "crt 100 ask turtles [ fd random-float 5 lt random-float 1080 fd random-float 4 ]"
  "07DEB6F4F007DB86CD8F2C2E10BD4E35CAD2B0CE")
+
+(defsimplecommandtest "if 1" "if 5 = 5 [ crt 10 ]"
+ "A925E39EC022967568D238D31F70F0A375024A89")
+
+(defsimplecommandtest "if 2" "if 5 = 4 [ crt 10 ]"
+ "E1DE30F072D785E0D0B59F28B0F7853E3D3E0D8B")
+
+(defsimplecommandtest "ifelse 1" "ifelse 5 = 5 [ crt 10 ] [crt 5 ] if-else 5 = 5 [ crt 10 ] [ crt 5 ]"
+ "2CF70DC9135754E77B64422C10E947E776E731E6")
+
+(defsimplecommandtest "ifelse 2" "ifelse 5 = 4 [ crt 10 ] [ crt 5 ] if-else 5 = 4 [ crt 10 ] [ crt 5 ]"
+ "A925E39EC022967568D238D31F70F0A375024A89")
-- 
2.25.1