all: implement match-file-comment for seting comment based on file name

The first thing that the program do is to detect which comment string to
be used when inserting SPDX identifiers in the file.

For each pattern in the "match-file-comment" section, the program will
match it with file name to get the comment prefix and suffix to be used
later.

User can add their own "match-file-comment" section as they like or modify
the existing one.

The "match-file-comment" can have empty prefix and suffix.
That means, if the file name match, it will create new file with
".license" suffix that contains SPDX identifiers only, instead of
inserting to the file.

1 files changed, 84 insertions, 16 deletions

diff --git a/README.md b/README.md
index 6a028c9..179c043 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,20 @@ SPDX-FileCopyrightText: 2026 M. Shulhan <ms@kilabit.info>
 
 # spdxconv
 
-spdxconv is a tool to convert and insert the SPDX identifiers.
+spdxconv is a tool to convert existing license and copyright into
+[SPDX](https://spdx.dev/)
+or insert the new identifiers.
+
+This tool works in tandem with [REUSE software](https://reuse.software).
+
+Features,
+
+- Customizable values for default license identifier and copyright
+- Customizable pattern for setting comment syntax based on file name
+- Customizable pattern for searching and capturing existing license through
+  regex
+- Customizable pattern for searching and capturing existing copyright year,
+  author, and contact through regex
 
 ## Background
 
@@ -59,6 +72,41 @@ license_identifier =
 file_copyright_text =
 max_line_match = 10
 
+[match-file-comment]
+pattern = "^.*\\.(adoc|asciidoc|c|cc|cpp|cs|dart|go|h|hh|hpp|java|js|jsx|jsonc|kt|kts|php|rs|sass|scss|swift|ts|tsx)$"
+comment_prefix = "//"
+
+[match-file-comment]
+pattern = "^.*\\.(bash|csh|dockerfile|env|gitignore|hcl|ipynb|make|pl|pm|py|ps1|rb|sh|tf|yaml|yml|zsh)$"
+prefix = "#"
+
+[match-file-comment]
+pattern = "^.*\\.(css)$"
+prefix = "/*"
+suffix = "*/"
+
+[match-file-comment]
+pattern = "^.*\\.(fxml|htm|html|html5|kml|markdown|md|xml)$"
+prefix = "<!--"
+suffix = "-->"
+
+[match-file-comment]
+pattern = "^.*\\.(lua|sql)$"
+prefix = "--"
+
+[match-file-comment]
+pattern = "^.*\\.(rst)$"
+prefix = ".."
+
+[match-file-comment]
+pattern = "^.*\\.(tex)$"
+prefix = "%"
+
+# File name that match with this pattern will have the ".license" file
+# created.
+[match-file-comment]
+pattern = "^.*\\.(apk|app|bz2|csv|doc|docx|exe|gif|gz|jpeg|jpg|json|pdf|png|ppt|pptx|svg|svgz|tar|tgz|xls|xlsx|zip)$"
+
 [match-license]
 pattern = "^(//+|#+)\\s+(.*)governed by a BSD-style(.*)$"
 license_identifier = BSD-3-Clause
@@ -69,8 +117,12 @@ pattern = "^(//+|#+)\\s+Copyright\\s+(?<year>\\d{4}),?\\s+(?<author>.*)\\s+<*(?<
 ```
 
 The configuration use the `ini` file format.
-You need to modify it by filling the "default" section, and can add another
-match-license and match-copyright pattern as required.
+You need to modify it by filling the "default" section before running the
+`scan` or `apply` command.
+
+You can add match-file-comment, match-license and match-copyright
+section as required, or modify the existing one to match with your use case.
+
 For quick references here are several rules that you need to be aware of,
 
 - The regex value must be enclosed in double quote
@@ -93,12 +145,28 @@ top and bottom of file for `SPDX-*` identifiers, `match-license`, and
 `match-copyright` before the program insert the default values.
 The default values is 10.
 
+### match-file-comment section
+
+The first thing that the program do is to detect which comment string to be
+used when inserting SPDX identifiers in the file.
+
+For each pattern in the "match-file-comment" section, the program will match
+it with file name to get the comment prefix and suffix to be used later.
+
+User can add their own "match-file-comment" section as they like or modify
+the existing one.
+
+The "match-file-comment" can have empty prefix and suffix.
+That means, if the file name match, it will create new file with ".license"
+suffix that contains SPDX identifiers only, instead of inserting to the file
+directly.
+
 ### match-license section
 
 <!-- REUSE-IgnoreStart -->
 
-The first thing that the program do is search for line that match
-with "SPDX-License-Identifier:".
+After program detect the file comment syntax to use, then it will search for
+line that match with "SPDX-License-Identifier:".
 
 <!-- REUSE-IgnoreEnd -->
 
@@ -208,22 +276,22 @@ identifier,
 ...
 ```
 
-Regular group are the file where program can detect the syntax of comment
-inside it.
+Regular group are list of file where program can detect its file comment to
+be used.
 Program will insert the new SPDX identifiers into the file using the
-detected comment syntax.
+comment syntax.
 
-Binary group are non-text file, for example images (like jpg, png) or
-executable files.
-For binary file, program will create new file with the same name as binary
-file plus additional suffix ".license".
+Binary group are list of non-text file, for example images (like jpg, png)
+or executable files.
+For binary file, program will create new file with the same name plus
+additional suffix ".license".
 Inside those "$name.license" file, the new SPDX identifiers will be inserted
 as defined in the report.
 
-Unknown group are regular file where program cannot detect the comment
-syntax used inside it.
-This files will not be processed, it is listed here so user can modify the
-configuration and rerun the scan command for the next cycle.
+Unknown group are list of file where program cannot detect the file comment
+to be used.
+This files will not be processed, it is listed here so user can inspect,
+modify the configuration, and rerun the scan command for the next cycle.
 
 ## apply command