From 804a2fe3c90c06a22a1eed5ea50d667ff3e7b08c Mon Sep 17 00:00:00 2001
From: Rose Hogenson <rhogenson@posteo.net>
Date: Wed, 29 Jun 2022 21:52:30 -0700
Subject: Add pattern matching for record types.

I like scheme because it's possible to add any convenient language
feature I can think of.
---
 csc/ir2.csc | 40 ++++++++++++++++++++++++++++++++++------
 1 file changed, 34 insertions(+), 6 deletions(-)

(limited to 'csc/ir2.csc')

diff --git a/csc/ir2.csc b/csc/ir2.csc
index 9b9397f..40109fe 100644
--- a/csc/ir2.csc
+++ b/csc/ir2.csc
@@ -78,7 +78,9 @@
           (only (csc list) all)
           (only (csc loop)
             loop
-            return))
+            return)
+          (only (csc match)
+            define-match-record-type))
   (begin
     ; This library defines the intermediate representation IR2.
     ; It's CPS time bitch.
@@ -90,6 +92,27 @@
     ;     - constant,
     ;     - lexical-ref,
     ;     - or library-ref
+    ;   After closure conversion, lexical refs are no longer allowed.
+    ;   Lexical refs are converted to one of the below data types.
+
+
+    ; A variable representing the address of a function in the same compilation
+    ; unit. This will be a constant after linking.
+    (define-match-record-type <label>
+      (make-label gensym)
+      label?
+      %label
+      (gensym label-gensym))
+
+
+    ; A local variable. This can be an argument to a function or the result of
+    ; a primitive.
+    (define-match-record-type <var>
+      (make-var gensym)
+      var?
+      %var
+      (gensym var-gensym))
+
 
     ; CPS expressions:
     ;   CPS expressions are similar to IR1 expressions,
@@ -98,9 +121,10 @@
 
 
     ; Modifies a library or lexically bound variable to the given atom.
-    (define-record-type <update>
+    (define-match-record-type <update>
       (make-update ref atom continuation)
       update?
+      %update
       (ref update-ref)
       (atom update-atom)
       (continuation update-continuation))
@@ -109,9 +133,10 @@
     ; Branches depending on the given atom.
     ; If it is true, continue with continuation true.
     ; If false, continue with continuation false.
-    (define-record-type <branch>
+    (define-match-record-type <branch>
       (make-branch atom true false)
       branch?
+      %branch
       (atom branch-atom)
       (true branch-true)
       (false branch-false))
@@ -120,9 +145,10 @@
     ; Applies a procedure to a list of arguments. Apply does not take a
     ; continuation. Instead the continuation will be passed as the first
     ; argument to the function.
-    (define-record-type <apply>
+    (define-match-record-type <apply>
       (make-apply procedure arguments)
       apply?
+      %apply
       (procedure apply-procedure)
       (arguments apply-arguments))
 
@@ -130,9 +156,10 @@
     ; A procedure. All closures are allocated in a fix expression. A closure
     ; does not take a continuation. Instead, the procedure will accept the
     ; continuation as an argument.
-    (define-record-type <closure>
+    (define-match-record-type <closure>
       (make-closure name arguments rest body)
       closure?
+      %closure
       (name closure-name)
       (arguments closure-arguments)
       (rest closure-rest)
@@ -141,9 +168,10 @@
 
     ; Defines a list of mutually recursive procedures.
     ; Functions is a list of closures, and body is an expression.
-    (define-record-type <fix>
+    (define-match-record-type <fix>
       (make-fix functions body)
       fix?
+      %fix
       (functions fix-functions)
       (body fix-body))
 
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