#413 support spdx_license_expression

 * some code skeleton is added, but the code is not working

src/attributecode/cmd.py

@@ -497,8 +497,8 @@ def transform(location, output, configuration, quiet, verbose):  # NOQA
 
 @click.option('--convert_to',
               required=True,
-              type=click.Choice(['djc', 'spdx']),
-              help='Convert to \'djc\' (aka \'license_expression\') from \'spdx_license_expression\',' 
+              type=click.Choice(['scancode', 'spdx']),
+              help='Convert to \'scancode\' (aka \'license_expression\') from \'spdx_license_expression\',' 
                     ' or convert to \'spdx\' (aka \'spdx_licesne_expression\') from \'license_expression\'.'
               )
 
@@ -533,16 +533,32 @@ def map_lic(location, output, convert_to, quiet, verbose):
     output_filename, output_file_extension = os.path.splitext(output)
     if not input_file_extension == output_file_extension:
         raise click.UsageError('ERROR: The file extension of the input and output are not the same.')
-    mapping(location, output, convert_to)
 
-"""
+    from attributecode.gen import load_inventory
+
+    errors, abouts = load_inventory(
+        location=location,
+        base_dir=output
+    )
+
+    halt = False
+
+    if errors:
+        halt_erorrs = ['CRITICAL', 'ERROR']
+        for severity, message in errors:
+            if severities.get(severity) in halt_erorrs:
+                halt = True
+
+    if not halt:
+        map_errors, abouts = mapping(abouts, convert_to)
+
     errors_count = report_errors(errors, quiet, verbose, log_file_loc=output + '-error.log')
     if not quiet:
         abouts_count = len(abouts)
         msg = '{abouts_count} .ABOUT files generated in {output}.'.format(**locals())
         click.echo(msg)
     sys.exit(errors_count)
-"""
+
 
 ######################################################################
 # Error management

src/attributecode/license_mapping.py

@@ -20,6 +20,7 @@
 from collections import Counter
 from collections import OrderedDict
 import io
+import os
 import json
 
 import attr
@@ -35,8 +36,28 @@
 from attributecode.util import replace_tab_with_spaces
 
 
-def mapping(location, output, convert_to):
-    errors, abouts = load_inventory(
-        location=location,
-        base_dir=output
-    )
+def mapping(abouts, convert_to):
+    errors = []
+    map_file_location = os.path.join(os.path.abspath(os.path.dirname(__file__)), 'spdx_mapping.json')
+    with open(map_file_location, 'r') as f:
+        map_file = json.loads(f.read())
+
+    # The map_file is a dictionary list with spdx license as the key and djc as the value.
+    # If 'convert_to == spdx', we need to create a new mapping file which the djc as the key and spdx as the value.
+    if convert_to == 'djc':
+        mapping_file = map_file.copy()
+    else:
+        mapping_file = {}
+        for k, v in map_file.items():
+            mapping_file[v] = k
+
+    errors, abouts = process_mapping(abouts, mapping_file)
+
+
+    return errors, abouts
+
+
+def process_mapping(abouts, mapping_file):
+    for about in abouts:
+        print(about)
+