Tools.h++ Manual

104011 Tandem Computers Incorporated 21-69

2.2 A one-character RE followed by a plus (+) matches one or more

occurrences of the RE. Hence, [a–z]+ matches one or more lower-case

characters.

2.3 A question mark (?) is an optional element. The preceeding RE can occur

zero or once in the string—no more. E.g. xy?z matches either xyz or xz .

2.4 The concatenation of REs is a RE that matches the corresponding

concatenation of strings. E.g., [A–Z][a–z]* matches any capitalized word.

Finally, the entire regular expression can be anchored to match only the

beginning or end of a line:

3.1 If the caret (^) is at the beginning of the RE, then the matched string

must be at the beginning of a line.

3.2 If the dollar sign ($) is at the end of the RE, then the matched string must

be at the end of the line.

The following escape codes can be used to match control characters:

backspace

ESC (escape)

formfeed

newline

carriage return

tab

xddd

the literal hex number 0xddd

Control code. E.g. \^D is "control-D"