From 484fffc6c5946b8d90decb803bfc9e318ba3a2e0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hugo=20H=C3=B6rnquist?= <hugo@lysator.liu.se>
Date: Fri, 23 Sep 2022 21:42:31 +0200
Subject: Document and parameterize peg-to-graph.

---
 module/scripts/peg-to-graph.scm | 46 +++++++++++++++++++++++++++--------------
 1 file changed, 30 insertions(+), 16 deletions(-)

diff --git a/module/scripts/peg-to-graph.scm b/module/scripts/peg-to-graph.scm
index 0472fd02..e2a829f9 100755
--- a/module/scripts/peg-to-graph.scm
+++ b/module/scripts/peg-to-graph.scm
@@ -4,10 +4,20 @@
   :use-module ((hnh module-introspection static-util) :select (get-forms))
   :use-module (srfi srfi-1)
   :use-module (ice-9 match)
+  :use-module (hnh util options)
+  :use-module (ice-9 getopt-long)
   :export (main))
 
+(define option-spec
+  `((engine (value #t)
+            (description "Graphviz rendering engine to use. Defaults to DOT"))
+    (output (single-char #\o)
+            (value #t)
+            (description "Name of output pdf"))))
+
 (define %summary "Output peg-pattern relations as a graphviz graph.")
-(define %include-in-list #t)
+(define %synopsis "peg-to-graph [options] <filename>")
+(define %help (format-arg-help option-spec))
 
 (define peg-primitives
   '(and or * + ? followed-by not-followed-by peg-any range
@@ -30,20 +40,24 @@
                        (unique-symbols (list body)))))))
 
 (define (main . args)
-  (when (< 1 (length args))
-    (format #t "Usage: guild peg-to-graph <filename>~%")
-    (exit 1))
+  (define options (getopt-long (cons "peg-to-graph" argrs)
+                               (getopt-opt option-spec)))
+  (define engine (option-ref options 'engine "dot"))
+  (define output-file (option-ref options 'output "lex2.pdf"))
+  (define input-file (let ((filenames (option-ref options '() '())))
+                       (when (null? filenames)
+                         (format #t "Usage: ~a~%" %summary)
+                         (exit 1))
+                       (car filenames)))
+
 
   (let ((graph (gv:digraph "G")))
-    (let ((input-file (car args)))
-      (for-each (lambda (form) handle-peg-form! graph form)
-                (filter (lambda (x)
-                          (and (list? x)
-                               (not (null? x))
-                               (eq? 'define-peg-pattern (car x))))
-                        (call-with-input-file input-file get-forms))))
-
-    (gv:layout graph "dot")
-    (gv:render graph "pdf" "lex2.pdf")
-
-    (display "done\n")))
+    (for-each (lambda (form) handle-peg-form! graph form)
+              (filter (lambda (x)
+                        (and (list? x)
+                             (not (null? x))
+                             (eq? 'define-peg-pattern (car x))))
+                      (call-with-input-file input-file get-forms)))
+
+    (gv:layout graph engine)
+    (gv:render graph "pdf" output-file)))
-- 
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