Leading sign format strings

Sub-String Name Sub-String Value Positive Negative
Leading-Sign "L" + Positive + Negative + Zero(1)

-or-

Req Req
"L" + "[" + Positive + "]" + Negative + Zero(1)

-or-

Opt Req
"L" + Positive + "[" + Negative + "]" + Zero(1)

-or-

Req Opt
"L" + Positive + Zero(1)

-or-

Req -
"L" + Negative + Zero(1) - Req