Start documenting the member-record module.

MODULES.md

@@ -60,6 +60,41 @@ action is required.
 
 ### Member Record
 
+This module encapsulates the data structure representing a single
+member record.
+
+    (make-member-record file-name file-path symlinks . args)
+
+* ```file-name``` - a symbol representing the primary filename
+* ```file-path``` - a string representing the path to the file
+* ```symlinks``` - a list of symbols representing symlinks
+* ```args``` - optional keyword arguments
+
+Creates a new member record dictionary. The three mandatory arguments
+are stored under respective keys and any keyword arguments are stored
+as keys obtained by converting the keyword to symbol with values
+following the keyword.
+
+The ```'id``` key is filled with any four-digit file-name or symlink
+converted to a number. Preferably the four-digit symbol should be the
+file-name but it is not required.
+
+    (member-record-input-file mr)
+
+* ```mr``` - a member record structure
+
+Returns an open file port to given member record underlying file. This
+function should be used by the parser to get the member file contents.
+
+    (member-record-set mr . args)
+
+* ```mr``` - a member record structure
+* ```args``` - optional keyword arguments
+
+Any keyword arguments are stored in the member record dictionary as
+keys obtained by converting the keyword to symbol with values
+following the keyword.
+
 ### Member Parser
 
 ### Member Info Printer