17 Sep
2021
17 Sep
'21
10:40 p.m.
Maybe there existed RE notations that were simply
copied ...
Ed was derived from Ken's earlier qed. Qed's descendant in Multics was
described in a 1969 GE document:
http://www.bitsavers.org/pdf/honeywell/multics/swenson/6906.multics-condens….
Unfortunately it describes regular expressions only sketchily by
example. However, alternation, symbolized by | with grouping by
parentheses, was supported in qed, whereas alternation was omitted
from ed. The GE document does not mention character classes; an
example shows how to use alternation for the same purpose.
Beginning-of-line is specified by a logical-negation symbol. In
apparent contradiction, the v1 manual says the meanings of [ and ^ are
the same in ed and (an unspecified version of) qed. My guess about the
discrepancies is no better than yours.
(I am amused by the title "condensed guide" for a manual in which each
qed request gets a full page of explanation. It exemplifies how Unix
split from Multics in matters of taste.)
Doug