+
+# Procedure index-query
+# The purpose of this function is to read the user's query and convert
+# it to the prefix query that IrTcl/YAZ uses to represent an RPN query.
+# Each entry in a search fields takes the form
+# [relOp][?]term[?]
+# Here, relOp is an optional relational operator and one of:
+# > < >= <= <>
+# which sets the Bib-1 relation to greater-than, less-than, etc.
+# The ? (question-mark) is also optional. A (?) on left-side indicates
+# left truncation; (?) on right-side indicates right-truncation; (?)
+# on both sides indicates both-left-and-right truncation.