regular_expressions

sregmatch_expr:=
regexps | reglex sexpr to sexpr with sregmatch_alternatives endmatch
regexps | regmatch sexpr with sregmatch_alternatives endmatch
sregmatch_alternatives:=
regexps | sregmatch_alternative+
sregmatch_alternative:=
regexps | | sre1 => sexpr
sregdef:=
regexps | regexp NAME = sre1 ;