From: Jean Privat <jean@pryen.org>
Date: Thu, 10 Sep 2015 02:40:42 +0000 (-0400)
Subject: nitiwiki: new module `markdown_highlight` to plug in an external highlighter
X-Git-Tag: v0.7.8~32^2~2
X-Git-Url: http://nitlanguage.org

nitiwiki: new module `markdown_highlight` to plug in an external highlighter

Signed-off-by: Jean Privat <jean@pryen.org>
---

diff --git a/contrib/nitiwiki/src/markdown_highlight.nit b/contrib/nitiwiki/src/markdown_highlight.nit
new file mode 100644
index 0000000..08751b0
--- /dev/null
+++ b/contrib/nitiwiki/src/markdown_highlight.nit
@@ -0,0 +1,99 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Extends the wiki with an external highlighter (or any processor) for code blocks
+module markdown_highlight
+import wiki_links
+
+redef class WikiConfig
+	# External highlighter command called to process block code.
+	#
+	# * key: `wiki.highlighter`
+	# * default: empty string, that means no external highlighter
+	# * example: `highlight --fragment -S "$1" --inline-css --enclose-pre`
+	#
+	# The external highlighter is a shell command invoked with `sh -c`.
+	# The meta information of the fence is passed as `$1`.
+	# *Important*: `$1` is given as is, thus is tainted. You SHOULD protect it with quotes in the command.
+	#
+	# By default, the highlighter is only called on fenced block code with a meta information.
+	# See `wiki.highlighter.default` to force the invocation of the highlighter on any code block.
+	#
+	# The output of the command will be inserted as is in the generated document.
+	# Therefore it is expected that the command returns a valid, complete and balanced HTML fragment.
+	# If the highlighter returns nothing (empty output), the internal rendering is used as a fall-back
+	# (as if the option was not set).
+	#
+	# Advanced usages can invoke a custom shell script instead of a standard command to
+	# check the argument, filter it, dispatch to various advanced commands, implement ad-hoc behaviors, etc.
+	var highlighter: String is lazy do
+		return value_or_default("wiki.highlighter", "")
+	end
+
+	# Default meta (i.e. language) to use to call the external highlighter.
+	#
+	# * key: `wiki.highlighter.default`
+	# * default: empty string, that means no default meta information.
+	# * example: `nit`
+	#
+	# When set, this configuration forces the external highlighter (see `wiki.highlighter`)
+	# to be called also on basic code block (with the indentation) and plain fenced code
+	# blocks (without meta information).
+	#
+	# The value is used as the `$1` argument of the configured highlighter command.
+	#
+	# Note: has no effect if `wiki.highlighter` is not set.
+	var highlighter_default: String is lazy do
+		return value_or_default("wiki.highlighter.default", "")
+	end
+end
+
+redef class NitiwikiDecorator
+	# Extends special cases for meta in fences
+	redef fun add_code(v, block) do
+		var highlighter = wiki.config.highlighter
+
+		# No highlighter, then defaults
+		if highlighter.is_empty then
+			super
+			return
+		end
+
+		var code = block.raw_content
+		var meta = block.meta or else wiki.config.highlighter_default
+
+		# No meta nor forced meta, then defaults
+		if meta.is_empty then
+			super
+			return
+		end
+
+		# Execute the command
+		wiki.message("Executing `{highlighter}` `{meta}` (in {context.src_path.as(not null)})", 2)
+		var proc = new ProcessDuplex("sh", "-c", highlighter, "", meta.to_s)
+		var res = proc.write_and_read(code)
+		if proc.status != 0 then
+			wiki.message("Warning: `{highlighter}` `{meta}` returned {proc.status} (in {context.src_path.as(not null)})", 0)
+		end
+
+		# Check the result
+		if res.is_empty then
+			# No result, then defaults
+			wiki.message("  `{highlighter}` produced nothing, process internally instead (in {context.src_path.as(not null)})", 2)
+			super
+			return
+		end
+		v.add(res)
+	end
+end
diff --git a/contrib/nitiwiki/src/nitiwiki.nit b/contrib/nitiwiki/src/nitiwiki.nit
index 71ab129..c5c6ebe 100644
--- a/contrib/nitiwiki/src/nitiwiki.nit
+++ b/contrib/nitiwiki/src/nitiwiki.nit
@@ -16,6 +16,7 @@
 module nitiwiki
 
 import wiki_html
+import markdown_highlight
 
 # Locate nit directory
 private fun compute_nit_dir(opt_nit_dir: OptionString): String do