UI-files scheme compiler and validator
lex DEFID|TAG|LEXID ([A-Za-z0-9_-]+)\s*
lex PIPE \|\s*
lex REGEXP (.+)
lex POSTOP ([?+-])\s*
lex BROP \(\s*
lex BRCL \)\s*
def GROUP
seq BROP EXPR BRCL
seq DEFID|LEXID
def POSTFIX
seq GROUP POSTOP?
def SEQ
seq POSTFIX+
def EXPR
seq SEQ (PIPE SEQ)*
rule lex LEXID (PIPE LEXID)* REGEXP
rule def DEFID
rule seq SEQ
rule case TAG (PIPE TAG)* SEQ
rule rule TAG (PIPE TAG)* ARGUMENTS
children rule
rule children TAG (PIPE TAG)*
root-rule lex | root-rule | rule | def