var fs = require('fs');
-type Some<T> = { _tag: "Some"; value: T };
-type None = {_tag: "None"};
+export type Some<T> = { _tag: "Some"; value: T };
+export type None = {_tag: "None"};
+
+/**
+ * wrap a x in a `Some(T)`
+ * @param x : variable to be wrapped.
+ * @returns wrapped `x`.
+ */
+function toSome<T>(x: T): Some<T>{
+ return { _tag: "Some", value: x};
+}
/**
* @description Like the `Some(a)` and `None` in Rust.
*
*/
export function match1Char(c : string) : (m: MatcheePair) => Maybe<MatcheePair> {
return (m : MatcheePair)=>{
+ if (m.remained.length == 0){
+ return { _tag: "None" };
+ }
const charToBeMatched = m.remained[0];
if (charToBeMatched === c){
return {_tag: "Some", value :{
}
};
+/**
+ *
+ * @param m : the `MatcheePair` to be consumed.
+ * @returns if the length of `m.remained` >= 1; consumes the matchee by 1 char and wraps it in `Some`,
+ * otherwise, returns `None`.
+ */
+export function matchAny(m : MatcheePair) : Maybe<MatcheePair>{
+ if (m.remained.length >= 1){
+ return {_tag: "Some", value :{
+ matched : m.matched + m.remained[0],
+ remained : m.remained.substring(1)}};
+ }else{
+ return {_tag: "None"};
+ }
+}
+
+/**
+ * @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"};
+ }
+ }
+};
+
/**
* convert the one-char string to codepoint.
* @param s : the string to code point.
/**
* @description thendo(input, f, ...) like
* a ==> f
+ * @param input: the wrapped input.
+ * @param f: the function to be applied.
+ *
+ * @returns:the applied wrapped result `MatcheePair`.
*/
export function thenDo<T>(input : Maybe<T>, f : Function) : Maybe<T>{
if (input._tag == "None"){
return f(inner);
}
}
+
+/**
+ * @description "or", like the regex `( f1 | f2 )` .
+ * It returns a function `f` of which the argument is`x`.
+ * if `f1(x)` is None, then `f` returns `f2(x)`. Otherwise,
+ * `F` returns `f1(x)`.
+ * @param f1 : 1st function to be compared
+ * @param f2 : 2nd function to be compared
+ * @returns:the combined function
+ */
+export function orDo<T>(f1 : Function, f2: Function) : (x : T ) => Maybe<T>{
+ return (x) => {
+ let f1x : Maybe<T> = (f1(x));
+ {
+ if (f1x._tag == "None"){
+ return f2(x);
+ }
+ else{
+ return f1x;
+ }
+ }
+ };
+}
+
+
+/**
+* @description repeating matching function `f`
+* zero or more times, like the asterisk `*` in regex `f*` .
+* @param f : the function to be repeated 0+ times.
+* @returns:the combined function
+*/
+export function zeroOrMoreDo<T>(f : Function): (x : T) => Maybe<T>{
+ return (x)=>{
+ var wrapped_old_x : Maybe<T> = {_tag: "Some", value : x};
+ var wrapped_new_x : Maybe<T> = wrapped_old_x;
+
+ while (wrapped_new_x._tag != "None"){
+ wrapped_old_x = wrapped_new_x;
+ wrapped_new_x = thenDo(wrapped_old_x, f);
+ };
+
+ return wrapped_old_x;
+ };
+}
+
+/**
+* @description Not. like the `^` inside regex of [^f].
+* returns a function `F(x)` such that if `f(x)` is `None`,
+* returns the x consuming a char; if `f(x)` is not None, F(x)
+* returns `None`.
+* @param f: the function forbidden to be matched.
+* @returns: combined function `F`.
+*/
+export function notDo<T>(f : Function): (x : T) => Maybe<T>{
+ return (x)=>{
+ let wrapped_x : Maybe<T> = {
+ _tag : "Some",
+ value : x
+ };
+ let f_x = thenDo(wrapped_x, f);
+
+ if (f_x._tag != "None"){
+ return {_tag:"None"};
+ }else{
+ return thenDo(wrapped_x, matchAny);
+ }
+ };
+}
+
+/**
+ * if `x` is matched by `f` once, returns `f(x)`. Otherwise,
+ * returns x
+ * similar to `?` in regex `f?`.
+ * @param f : the function to be matched
+ * @returns return wrapped f(x)
+ */
+export function zeroOrOnceDo<T>(f : Function): (x : T) => Maybe<T>{
+ return (x)=>{
+ var wrapped_old_x : Maybe<T> = {_tag: "Some", value : x};
+ var wrapped_new_x = thenDo(wrapped_old_x, f);
+
+ if (wrapped_new_x._tag != "None"){
+ return wrapped_new_x;
+ }else{
+ return wrapped_old_x;
+ }
+ };
+}
+
+
+export function tokenize(input : string){
+ var input_matchee_pair : Maybe<MatcheePair> = toSome(
+ {matched:"",
+ remained: input});
+
+ // integer = ([+]|[-])?\d\d*
+ let integer = (x : MatcheePair) =>
+ { let wrapped_x = toSome(x);
+ let plusMinus = orDo(match1Char('+'), match1Char('-')); // ([+]|[-])
+ let d = matchRange('0','9'); // \d
+ return thenDo(thenDo(thenDo(wrapped_x,
+ zeroOrOnceDo(plusMinus)),d),
+ zeroOrMoreDo(d));
+ }
+ console.log(input+", result: ");
+ console.log(thenDo(input_matchee_pair, integer));
+ // TODO: id, string, space, basic operator, 3 marks: @, {, }.
+
+}
+
+tokenize("+123");
+tokenize("123");
+tokenize("-123");
+tokenize(" 123");
+tokenize("c123");
projects / clo / blobdiff