From 4230b1824fa484286a13bb55068b63ad3656b0bd Mon Sep 17 00:00:00 2001
From: Alex Karle <alex@alexkarle.com>
Date: Wed, 5 Oct 2022 20:54:20 -0400
Subject: [PATCH] parser: Add basic parser types from ch. 5

This gets interesting because I'm not really trying to implement the
visitor pattern in Scheme. Setting the record printers feels awfully
like Java's toString() though
---
 fisl.scm   |  3 +++
 parser.scm | 25 +++++++++++++++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 parser.scm

diff --git a/fisl.scm b/fisl.scm
index 277ae26..3094da1 100755
--- a/fisl.scm
+++ b/fisl.scm
@@ -2,14 +2,17 @@
 ;; fisl -- fisl is scheme lox
 (load "scanner.scm")
 (load "util.scm")
+(load "parser.scm")
 
 (import (chicken io)
         (chicken base)
         (chicken format)
         scanner
+        parser
         util)
 
 (define (run code fname)
+  (parse)
     (map print (scan code fname)))
 
 (define (run-prompt)
diff --git a/parser.scm b/parser.scm
new file mode 100644
index 0000000..d0b8ee1
--- /dev/null
+++ b/parser.scm
@@ -0,0 +1,25 @@
+(module parser (parse)
+
+  (import scheme
+          (chicken base)
+          (chicken format))
+
+  (define-record binary left operator right)
+  (set-record-printer! binary
+    (lambda (x out) (fprintf out "(~S ~S ~S)" (binary-operator x) (binary-left x) (binary-right x))))
+
+  (define-record grouping expression)
+  (set-record-printer! grouping
+    (lambda (x out) (fprintf out "(group ~S)" (grouping-expression x))))
+
+  (define-record literal value)
+  (set-record-printer! literal
+    (lambda (x out) (fprintf out "~S" (literal-value x))))
+
+  (define-record unary operator right)
+  (set-record-printer! unary
+    (lambda (x out) (fprintf out "(~S ~S)" (unary-operator x) (unary-right x))))
+
+  (define (parse)
+    (print (make-binary (make-unary "-" (make-literal 123)) "*" (make-grouping (make-literal 42)))))
+)
--
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