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Group syntax entities by combinator precedence
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@frenic
frenic committed Apr 6, 2018
1 parent 8083a2e commit 054dcce
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52 changes: 51 additions & 1 deletion __tests__/parser.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@ describe('parsing', () => {
});

it('parses components', () => {
expect(parse('something <color> [ something <color> ]')).toMatchObject([
expect(parse('something <something> [ something <something> ]')).toMatchObject([
{ component: Component.Keyword },
{},
{ component: Component.DataType },
Expand Down Expand Up @@ -113,5 +113,55 @@ describe('parsing', () => {
],
},
]);

expect(parse('something && something something || something')).toMatchObject([
{
component: Component.Group,
entities: [
{},
{ combinator: Combinator.DoubleAmpersand },
{
component: Component.Group,
entities: [{}, { combinator: Combinator.Juxtaposition }, {}],
},
],
},
{ combinator: Combinator.DoubleBar },
{},
]);

expect(parse('something || something something && something')).toMatchObject([
{},
{ combinator: Combinator.DoubleBar },
{
component: Component.Group,
entities: [
{
component: Component.Group,
entities: [{}, { combinator: Combinator.Juxtaposition }, {}],
},
{ combinator: Combinator.DoubleAmpersand },
{},
],
},
]);

expect(parse('something | something something something')).toMatchObject([
{},
{ combinator: Combinator.SingleBar },
{
component: Component.Group,
entities: [{}, { combinator: Combinator.Juxtaposition }, {}, { combinator: Combinator.Juxtaposition }, {}],
},
]);

expect(parse('something something something | something')).toMatchObject([
{
component: Component.Group,
entities: [{}, { combinator: Combinator.Juxtaposition }, {}, { combinator: Combinator.Juxtaposition }, {}],
},
{ combinator: Combinator.SingleBar },
{},
]);
});
});
159 changes: 137 additions & 22 deletions src/parser.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -11,15 +11,16 @@ export enum Component {
Group,
}

// Higher number is higher precedence
export enum Combinator {
/** Components are mandatory and should appear in that order */
Juxtaposition,
Juxtaposition = 0,
/** Components are mandatory but may appear in any order */
DoubleAmpersand,
DoubleAmpersand = 1,
/** At least one of the components must be present, and they may appear in any order */
DoubleBar,
DoubleBar = 2,
/** Exactly one of the components must be present */
SingleBar,
SingleBar = 3,
}

export enum Multiplier {
Expand Down Expand Up @@ -72,7 +73,6 @@ export type ComponentType = INonGroupData | IGroupData;

export interface ICombinator {
entity: Entity.Combinator;
multiplier: MultiplierType | null;
combinator: Combinator;
}

Expand All @@ -81,7 +81,7 @@ export interface IFunction {
multiplier: MultiplierType | null;
}

interface IUnknown {
export interface IUnknown {
entity: Entity.Unknown;
multiplier: MultiplierType | null;
}
Expand All @@ -92,10 +92,29 @@ const REGEX_ENTITY = /(?:^|\s)((?:[\w]+\([^\)]*\))|[^\s*+?#!{]+)([*+?#!]|{(\d+),
const REGEX_DATA_TYPE = /^(<[^>]+>)/g;
const REGEX_KEYWORD = /^([\w-]+)/g;

const combinators: { [key: number]: ICombinator } = {
[Combinator.Juxtaposition]: {
entity: Entity.Combinator,
combinator: Combinator.Juxtaposition,
},
[Combinator.DoubleAmpersand]: {
entity: Entity.Combinator,
combinator: Combinator.DoubleAmpersand,
},
[Combinator.DoubleBar]: {
entity: Entity.Combinator,
combinator: Combinator.DoubleBar,
},
[Combinator.SingleBar]: {
entity: Entity.Combinator,
combinator: Combinator.SingleBar,
},
};

export default function parse(syntax: string): EntityType[] {
const levels: EntityType[][] = [[]];
const deepestLevel = () => levels[levels.length - 1];
let previousMatchWasComponent = false;

let entityMatch: RegExpExecArray | null;
while ((entityMatch = REGEX_ENTITY.exec(syntax))) {
const [, value, ...rawMultiplier] = entityMatch;
Expand All @@ -104,27 +123,27 @@ export default function parse(syntax: string): EntityType[] {
previousMatchWasComponent = false;
continue;
} else if (value.indexOf('&&') === 0) {
deepestLevel().push(combinatorData(Combinator.DoubleAmpersand, multiplierData(rawMultiplier)));
deepestLevel().push(combinators[Combinator.DoubleAmpersand]);
previousMatchWasComponent = false;
continue;
} else if (value.indexOf('||') === 0) {
deepestLevel().push(combinatorData(Combinator.DoubleBar, multiplierData(rawMultiplier)));
deepestLevel().push(combinators[Combinator.DoubleBar]);
previousMatchWasComponent = false;
continue;
} else if (value.indexOf('|') === 0) {
deepestLevel().push(combinatorData(Combinator.SingleBar, multiplierData(rawMultiplier)));
deepestLevel().push(combinators[Combinator.SingleBar]);
previousMatchWasComponent = false;
continue;
} else if (value.indexOf(']') === 0) {
const definitions = levels.pop();
if (definitions) {
deepestLevel().push(componentGroupData(definitions, multiplierData(rawMultiplier)));
deepestLevel().push(componentGroupData(groupByPrecedence(definitions), multiplierData(rawMultiplier)));
}
previousMatchWasComponent = true;
continue;
} else {
if (previousMatchWasComponent === true) {
deepestLevel().push(combinatorData(Combinator.Juxtaposition));
if (previousMatchWasComponent) {
deepestLevel().push(combinators[Combinator.Juxtaposition]);
}

if (value.indexOf('[') === 0) {
Expand All @@ -149,15 +168,54 @@ export default function parse(syntax: string): EntityType[] {
deepestLevel().push({ entity: Entity.Unknown, multiplier: multiplierData(rawMultiplier) });
}

return levels[0];
function deepestLevel() {
return levels[levels.length - 1];
}

return groupByPrecedence(levels[0]);
}

function combinatorData(combinator: Combinator, multiplier: MultiplierType | null = null): ICombinator {
return {
entity: Entity.Combinator,
combinator,
multiplier,
};
export function isFunction(entity: EntityType): entity is IFunction {
return entity.entity === Entity.Function;
}

export function isComponent(entity: EntityType): entity is ComponentType {
return entity.entity === Entity.Component;
}

export function isCombinator(entity: EntityType): entity is ICombinator {
return entity.entity === Entity.Combinator;
}

export function isCurlyBracetMultiplier(multiplier: MultiplierType): multiplier is IMultiplierCurlyBracet {
return multiplier.sign === Multiplier.CurlyBracet;
}

export function isMultiplied(multiplier: MultiplierType) {
return (
(isCurlyBracetMultiplier(multiplier) && (multiplier.min > 1 || multiplier.max > 1)) ||
multiplier.sign === Multiplier.Asterisk ||
multiplier.sign === Multiplier.PlusSign ||
multiplier.sign === Multiplier.HashMark ||
multiplier.sign === Multiplier.ExclamationPoint
);
}

export function isMandatoryEntity(entity: EntityType) {
if (isCombinator(entity)) {
return entity === combinators[Combinator.DoubleAmpersand] || entity === combinators[Combinator.Juxtaposition];
}

if (entity.multiplier) {
return (
(isCurlyBracetMultiplier(entity.multiplier) && entity.multiplier.min === 0) ||
entity.multiplier.sign === Multiplier.PlusSign ||
entity.multiplier.sign === Multiplier.HashMark ||
entity.multiplier.sign === Multiplier.ExclamationPoint
);
}

return true;
}

function componentData(
Expand All @@ -173,7 +231,7 @@ function componentData(
};
}

function componentGroupData(entities: EntityType[], multiplier: MultiplierType | null): ComponentType {
function componentGroupData(entities: EntityType[], multiplier: MultiplierType | null = null): ComponentType {
return {
entity: Entity.Component,
component: Component.Group,
Expand All @@ -198,8 +256,65 @@ function multiplierData(raw: string[]): MultiplierType | null {
case '!':
return { sign: Multiplier.ExclamationPoint };
case '{':
return { sign: Multiplier.CurlyBracet, min: +raw[1], max: +raw[2] };
return { sign: Multiplier.CurlyBracet, min: Number(raw[1]), max: Number(raw[2]) };
default:
return null;
}
}

function groupByPrecedence(entities: EntityType[], precedence: number = Combinator.SingleBar): EntityType[] {
if (precedence < 0) {
// We've reached the lowest precedence possible
return entities;
}

const combinator = combinators[precedence];
const combinatorIndexes: number[] = [];

// Search for indexes where the combinator is used
for (let i = entities.indexOf(combinator); i > -1; i = entities.indexOf(combinator, i + 1)) {
combinatorIndexes.push(i);
}

const nextPrecedence = precedence - 1;

if (combinatorIndexes.length === 0) {
return groupByPrecedence(entities, nextPrecedence);
}

const groupedEntities: EntityType[] = [];

// Yes, what you see is correct: it's index of indexes
for (
let i = 0;
// Add one loop to finnish up the last entities
i < combinatorIndexes.length + 1;
i++
) {
const currentIndex = combinatorIndexes[i];

const sectionEntities = entities.slice(
i > 0
? combinatorIndexes[i - 1] + 1
: // Slice from beginning
0,
i < combinatorIndexes.length
? currentIndex
: // Slice to end
entities.length,
);

// Only group if there's more than one entity in between
if (sectionEntities.length > 1) {
groupedEntities.push(componentGroupData(groupByPrecedence(sectionEntities, nextPrecedence)));
} else {
groupedEntities.push(...sectionEntities);
}

if (i < combinatorIndexes.length) {
groupedEntities.push(entities[currentIndex]);
}
}

return groupedEntities;
}
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