From 64ed9fb4581b290c6c64152e577ee166ff1d4dd7 Mon Sep 17 00:00:00 2001
From: Arun Isaac
Date: Mon, 13 Dec 2021 17:41:19 +0530
Subject: ccwl: Escape only the double quote character in graphviz output.

* ccwl/graphviz.scm: Import (ice-9 string-fun).
(serialize): When quoting strings, escape only the double quote
character.
* tests/graphviz.scm ("do not escape backslashes"): New test case.
---
 ccwl/graphviz.scm  |  9 +++++----
 tests/graphviz.scm | 13 +++++++++++++
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/ccwl/graphviz.scm b/ccwl/graphviz.scm
index fbef971..a3f4036 100644
--- a/ccwl/graphviz.scm
+++ b/ccwl/graphviz.scm
@@ -29,6 +29,7 @@
   #:use-module (srfi srfi-26)
   #:use-module (srfi srfi-28)
   #:use-module (ice-9 match)
+  #:use-module (ice-9 string-fun)
   #:use-module (ccwl ccwl)
   #:use-module (ccwl utils)
   #:export (workflow->dot))
@@ -129,15 +130,15 @@ symbol, a string, or a <html-string> object."
      ;; Surround HTML strings in <>, and don't escape.
      ((html-string? object)
       (format "<~a>" str))
-     ;; Don't escape safe strings.
+     ;; Don't quote safe strings.
      ((string-every (char-set-union (char-set-intersection char-set:letter+digit
                                                            char-set:ascii)
                                     (char-set #\_))
                     str)
       str)
-     ;; Escape strings with unsafe characters.
-     (else (call-with-output-string
-             (cut write str <>))))))
+     ;; Quote strings with unsafe characters.
+     (else
+      (format "\"~a\"" (string-replace-substring str "\"" "\\\""))))))
 
 (define* (graph->dot graph #:optional (port (current-output-port)) (level 0))
   "Render GRAPH, a <graph> object, in the graphviz dot syntax to
diff --git a/tests/graphviz.scm b/tests/graphviz.scm
index 5853616..bb99edc 100644
--- a/tests/graphviz.scm
+++ b/tests/graphviz.scm
@@ -45,4 +45,17 @@
                                         `((label . ,(html-string "<table><tr><td>bar</td></tr></table>"))))))
        port))))
 
+(test-equal "do not escape backslashes"
+  "digraph foo {
+  bar [label=\"foo\\lbar\"];
+}
+"
+  (call-with-output-string
+    (lambda (port)
+      (graph->dot
+       (graph 'foo
+              #:nodes (list (graph-node 'bar
+                                        `((label . "foo\\lbar")))))
+       port))))
+
 (test-end "graphviz")
-- 
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