-/**
- * @description
- * it returns a function which test if the first char of the `remained` part of
- * the argument of the function is between `l` and `u`, if it's true, update the `MatchedPair` wrapped
- * in `Some`. Otherwise, it returns `None`.
- * * @param l : lower bound char, 1-char string
- * * @param u : upper bound char, 1-char string
- * @returns the updated `MatchedPair` wrapped in `Some(x)` or `None`.
- */
-export function matchRange(l : string, u : string) : (m: MatcheePair) => Maybe<MatcheePair> {
- let lCodepoint = charToCodepoint(l);
- let uCodepoint = charToCodepoint(u);
- if (l > u){
- throw new Error("Error: the codepoint of `"+l+"` is not smaller than `"+u+"`)");
- }
- return (m : MatcheePair)=>{
- if (m.remained.length < 1){
- return {_tag : "None"};
- }
- const charToBeMatched = m.remained[0];
- const codePointToBeMatched = charToCodepoint(charToBeMatched);
- if (codePointToBeMatched >= lCodepoint && codePointToBeMatched <= uCodepoint){
- return {_tag: "Some", value :{
- matched : m.matched + charToBeMatched,
- remained : m.remained.substring(1)}};
- }
- else{
- return {_tag: "None"};
- }
- }
-};