From fdcf4be12c7c8913ccd26ebcab7cb05eb2abaa48 Mon Sep 17 00:00:00 2001
From: bd <bdunaisky@umass.edu>
Date: Mon, 4 Nov 2024 23:34:54 -0500
Subject: Add keywords to lexer

---
 manifest.scm                        |  1 +
 src/gscc                            |  8 +++++---
 src/modules/lexer/lexer.scm         | 12 +++++++++++-
 src/unit-tests/lexer/lexer-test.scm |  6 +++++-
 4 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/manifest.scm b/manifest.scm
index be6c84e..8d1b86e 100644
--- a/manifest.scm
+++ b/manifest.scm
@@ -1,5 +1,6 @@
 (specifications->manifest
  '(
    "gcc-toolchain"
+   "guile"
    "python"
    ))
diff --git a/src/gscc b/src/gscc
index 8914016..82ed649 100755
--- a/src/gscc
+++ b/src/gscc
@@ -33,9 +33,11 @@ file on a success."
 
 (define (process file parse? assemble?)
   "Driver for lexing, parsing, and assembly generation."
-  (let ((port (open-input-file file)))
-    (set-current-input-port port)
-    (read-tokens)
+  (let* ((port (open-input-file file))
+	 (tokens (begin (set-current-input-port port)
+			(read-tokens))))
+    ;; (when parse?
+    ;;   )
     (close-input-port port)))
 
 (define (postprocess file dest)
diff --git a/src/modules/lexer/lexer.scm b/src/modules/lexer/lexer.scm
index e07ab67..dae7107 100644
--- a/src/modules/lexer/lexer.scm
+++ b/src/modules/lexer/lexer.scm
@@ -30,7 +30,7 @@ current input port."
        'semi-colon)
 
       ((char-alphabetic? chr)
-       (read-identifier chr))
+       (lookup-keyword (read-identifier chr)))
 
       ((char-numeric? chr)
        (read-constant chr))
@@ -57,3 +57,13 @@ current input port."
 	     (read-identifier-helper (cons (read-char) chrs-so-far)))
 	    (#t (reverse chrs-so-far)))))
   (list->string (read-identifier-helper (list chr))))
+
+(define (lookup-keyword id)
+  "Given identifier ID, converts it to a keyword
+if one is known."
+  (let ((found (assoc
+		id
+		'(("int" . int)
+		  ("void" . void)
+		  ("return" . return)))))
+    (if found (cdr found) id)))
diff --git a/src/unit-tests/lexer/lexer-test.scm b/src/unit-tests/lexer/lexer-test.scm
index eb41b83..48291b9 100644
--- a/src/unit-tests/lexer/lexer-test.scm
+++ b/src/unit-tests/lexer/lexer-test.scm
@@ -65,8 +65,12 @@
 (test-error (read-this "1foo")
 	    (read-tokens))
 
+(test-equal (read-this "void")
+  '(void)
+  (read-tokens))
+
 (test-equal (read-this "int main(void) {return 2;}")
-  '("int" "main" left-paren "void" right-paren open-brace "return" 2 semi-colon close-brace)
+  '(int "main" left-paren void right-paren open-brace return 2 semi-colon close-brace)
   (read-tokens))
 
 
-- 
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