[incubator-annotator] 03/09: Add debug tool for parser

[ge...@apache.org]

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gerben pushed a commit to branch fragment-tests
in repository https://gitbox.apache.org/repos/asf/incubator-annotator.git

commit 16308314883d4a133cc396596b180877e26550af
Author: Gerben <ge...@treora.com>
AuthorDate: Fri Apr 3 12:42:29 2020 +0200

    Add debug tool for parser
---
 packages/fragment-identifier/src/fragment.pegjs | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/packages/fragment-identifier/src/fragment.pegjs b/packages/fragment-identifier/src/fragment.pegjs
index 8e6d22c..c19c6bd 100644
--- a/packages/fragment-identifier/src/fragment.pegjs
+++ b/packages/fragment-identifier/src/fragment.pegjs
@@ -1,3 +1,17 @@
+{
+    function debug(input, range) {
+      // Prints the location of the parser.
+      // Use e.g. in an action: { debug(input, range); return text(); }
+      const [start, end] = range();
+      const underline = (end > start + 1)
+        ? ' '.repeat(start) + '\\' + '_'.repeat(end - start - 2) + '/'
+        : ' '.repeat(start) + '^';
+      console.log(input);
+      console.log(underline);
+    }
+}
+
+
 start =
     top