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Refactor navigators #25

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278b7bd
Refactor
lucmartens Nov 11, 2018
2511e71
experiment with navigators
lucmartens Nov 12, 2018
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230 changes: 30 additions & 200 deletions src/core.js
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Original file line number Diff line number Diff line change
@@ -1,220 +1,50 @@
const _ = require("./impl");
const navs = require("./navs");

const NONE = _.NONE;
module.exports.NONE = NONE;
const COMPILED = Symbol("COMPILED");

const navigator = m => {
const fn = next => operation => m[operation](next(operation));
fn.isNavigator = true;
return fn;
};

module.exports.ALL = navigator({
select: next => struct => _.flatMap(next, struct),
transform: next => struct => _.map(next, struct)
});

module.exports.MAP_VALS = navigator({
select: next => struct => _.flatMap(next, _.values(struct)),
transform: next => struct => _.mapValues(next, struct)
});

module.exports.MAP_KEYS = navigator({
select: next => struct => _.flatMap(next, _.keys(struct)),
transform: next => struct => _.mapKeys(next, struct)
});

module.exports.MAP_ENTRIES = navigator({
select: next => struct => _.flatMap(next, _.entries(struct)),
transform: next => struct => _.mapEntries(next, struct)
});

module.exports.FIRST = navigator({
select: next => struct => (_.isEmpty(struct) ? [] : next(struct[0])),
transform: next => struct =>
_.isEmpty(struct) ? struct : _.updateArray(0, next, struct)
});

module.exports.LAST = navigator({
select: next => struct =>
_.isEmpty(struct) ? [] : next(struct[struct.length - 1]),
transform: next => struct =>
_.isEmpty(struct) ? struct : _.updateArray(struct.length - 1, next, struct)
});

module.exports.BEGINNING = navigator({
select: next => struct => [],
transform: next => struct => {
const result = next([]);
return _.isArray(result)
? _.concat(result, struct)
: _.cons(result, struct);
}
});

module.exports.END = navigator({
select: next => struct => [],
transform: next => struct => {
const result = next([]);
return _.isArray(result)
? _.concat(struct, result)
: _.conj(struct, result);
}
});

module.exports.BEFORE_ELEM = navigator({
select: next => struct => NONE,
transform: next => struct => {
const result = next(NONE);
return result === NONE ? struct : _.cons(result, struct);
}
});

module.exports.AFTER_ELEM = navigator({
select: next => struct => NONE,
transform: next => struct => {
const result = next(NONE);
return result === NONE ? struct : _.conj(struct, result);
}
});

module.exports.key = key =>
navigator({
select: next => struct => next(struct[key]),
transform: next => struct => {
const result = next(struct[key]);
return result === NONE ? _.omit(key, struct) : _.set(key, result, struct);
}
});

module.exports.nth = index =>
navigator({
select: next => struct => next(struct[index]),
transform: next => struct => _.updateArray(index, next, struct)
});

module.exports.pred = pred =>
navigator({
select: next => struct => (pred(struct) ? next(struct) : []),
transform: next => struct => (pred(struct) ? next(struct) : struct)
});

module.exports.parser = (parse, unparse) =>
navigator({
select: next => struct => next(parse(struct)),
transform: next => struct => unparse(next(parse(struct)))
});

module.exports.submap = keys =>
navigator({
select: next => struct => next(_.pick(keys, struct)),
transform: next => struct => _.merge(struct, next(_.pick(keys, struct)))
});
const isCompiled = obj => typeof obj === "function" && obj[COMPILED];

module.exports.view = fn =>
navigator({
select: next => struct => next(fn(struct)),
transform: next => struct => next(fn(struct))
});

module.exports.filterer = path => {
const compiledPath = compile(path);
return navigator({
select: next => struct =>
next(
_.reduce(
(acc, v) => {
const result = module.exports.compiledSelect(compiledPath, v);
return result.length ? _.conj(acc, v) : acc;
},
[],
struct
)
),
transform: next => struct => {
const mapping = {};
const filtered = [];
for (let [i, j] = [0, 0]; i < struct.length; i++) {
const selected = module.exports.compiledSelect(compiledPath, struct[i]);
if (selected.length) {
mapping[i] = j;
j++;
filtered.push(...selected);
}
}

const transformed = next(filtered);
const result = [];
for (let i = 0; i < struct.length; i++) {
const mappedIdx = mapping[i];

if (mappedIdx !== undefined) {
if (transformed[mappedIdx] !== undefined) {
result.push(transformed[mappedIdx]);
}
} else {
result.push(struct[i]);
}
}

return result;
}
});
};

const resolveNavigator = nav => {
const type = typeof nav;
if (type === "function" && nav.isNavigator) {
return nav;
}

switch (type) {
case "string":
return module.exports.key(nav);
case "number":
return module.exports.nth(nav);
case "function":
return module.exports.pred(nav);
const compile = path => {
if (isCompiled(path)) {
return path;
}
};

const compile = path => {
path = Array.isArray(path) ? path : [path];
let defer;

const compiled = _.reduceRight(
(acc, nav) => resolveNavigator(nav)(acc),
op => v => defer(v),
Array.isArray(path) ? path : [path]
);

return (operation, lastFn, struct) => {
defer = lastFn;
return compiled(operation)(struct);
const reducer = (acc, nav) => {
return isCompiled(nav)
? op => struct => nav(op, acc(op), struct)
: navs.resolveNavigator(nav)(acc);
};
};

module.exports.compile = compile;
const compiled = _.reduceRight(reducer, op => defer, path);

module.exports.select = (path, struct) =>
compile(path)("select", v => [v], struct);
const fn = (operation, leafFn, struct) => {
defer = leafFn;
return compiled(operation)(struct);
};

module.exports.compiledSelect = (compiledPath, struct) =>
compiledPath("select", v => [v], struct);
fn[COMPILED] = true;
return fn;
};

module.exports.selectOne = (path, struct) =>
compile(path)("select", v => v, struct);
const select = (path, struct) => compile(path)("select", v => [v], struct);

module.exports.compiledSelectOne = (compiledPath, struct) =>
compiledPath("select", v => v, struct);
const selectOne = (path, struct) => compile(path)("select", v => v, struct);

module.exports.transform = (path, update, struct) =>
const transform = (path, update, struct) =>
compile(path)("transform", update, struct);

module.exports.compiledTransform = (compiledPath, update, struct) =>
compiledPath("transform", update, struct);

module.exports.setval = (path, value, struct) =>
const setval = (path, value, struct) =>
compile(path)("transform", () => value, struct);

module.exports.compiledSetval = (compiledPath, value, struct) =>
compiledPath("transform", () => value, struct);
module.exports = {
compile,
select,
selectOne,
transform,
setval
};
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