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feat: add node helpers to scanner #15

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merged 4 commits into from
Dec 24, 2020
Merged

feat: add node helpers to scanner #15

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8c6f234
refactor: remove ambiguous whitespace consumer from scanner
byCedric Dec 24, 2020
049689b
feat: add node enter, exit, and abort methods
byCedric Dec 24, 2020
ad0ae52
refactor: fallback to expected node type when aborting
byCedric Dec 24, 2020
6ef9963
chore: update snapshots to match fixed positioning
byCedric Dec 24, 2020
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162 changes: 44 additions & 118 deletions index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -7,11 +7,8 @@ const { isWhitespace, isNewline, isParens } = require('./lib/type-checks')
*/
function message (commitText) {
const scanner = new Scanner(commitText.trim())
const start = scanner.position()
const node = {
type: 'message',
children: []
}
const node = scanner.enter('message', [])

// <summary>
const s = summary(scanner)
if (s instanceof Error) {
Expand All @@ -20,8 +17,7 @@ function message (commitText) {
node.children.push(s)
}
if (scanner.eof()) {
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
}

// <summary> <newline>* <body>
Expand All @@ -30,11 +26,10 @@ function message (commitText) {
scanner.next()
}
} else {
throw invalidToken(scanner, ['none'])
throw scanner.abort(node)
}
node.children.push(body(scanner))
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
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This is a much nicer API 😄

}

/*
Expand All @@ -43,11 +38,7 @@ function message (commitText) {
*
*/
function summary (scanner) {
const start = scanner.position()
const node = {
type: 'summary',
children: []
}
const node = scanner.enter('summary', [])

const t = type(scanner)
if (t instanceof Error) {
Expand All @@ -67,7 +58,7 @@ function summary (scanner) {
node.children.push(s)
}
if (scanner.peek() !== ')') {
return invalidToken(scanner, [')'])
return scanner.abort(node, [')'])
}
scanner.next()
}
Expand All @@ -83,25 +74,20 @@ function summary (scanner) {
// ... ": " <text>
const sep = separator(scanner)
if (sep instanceof Error) {
return invalidToken(scanner, [!s && '(', !b && '!', ':'])
return scanner.abort(node, [!s && '(', !b && '!', ':'])
} else {
node.children.push(sep)
}

node.children.push(text(scanner))
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
}

/*
* <type> ::= 1*<any UTF8-octets except newline or parens or ["!"] ":" or whitespace>
*/
function type (scanner) {
const start = scanner.position()
const node = {
type: 'type',
value: ''
}
const node = scanner.enter('type', '')
while (!scanner.eof()) {
const token = scanner.peek()
if (isParens(token) || isWhitespace(token) || isNewline(token) || token === '!' || token === ':') {
Expand All @@ -110,42 +96,32 @@ function type (scanner) {
node.value += scanner.next()
}
if (node.value === '') {
return invalidToken(scanner, ['type'])
return scanner.abort(node)
} else {
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
}
}

/*
* <text> ::= 1*<any UTF8-octets except newline>
*/
function text (scanner) {
const start = scanner.position()
const node = {
type: 'text',
value: ''
}
const node = scanner.enter('text', '')
while (!scanner.eof()) {
const token = scanner.peek()
if (isNewline(token)) {
break
}
node.value += scanner.next()
}
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
}

/*
* <scope> ::= 1*<any UTF8-octets except newline or parens>
*/
function scope (scanner) {
const start = scanner.position()
const node = {
type: 'scope',
value: ''
}
const node = scanner.enter('scope', '')
while (!scanner.eof()) {
const token = scanner.peek()
if (isParens(token) || isNewline(token)) {
Expand All @@ -155,10 +131,9 @@ function scope (scanner) {
}

if (node.value === '') {
return invalidToken(scanner, ['scope'])
return scanner.abort(node)
} else {
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
}
}

Expand All @@ -168,16 +143,12 @@ function scope (scanner) {
* | [<text>]
*/
function body (scanner) {
const node = {
type: 'body',
children: []
}
const start = scanner.position()
const node = scanner.enter('body', [])
// 1*<footer>
while (!scanner.eof()) {
const f = footer(scanner)
if (f instanceof Error) {
scanner.rewind(start)
scanner.abort(node)
node.children = []
// [<text>], <newline>, <body>*
const t = text(scanner)
Expand All @@ -198,19 +169,14 @@ function body (scanner) {
node.children.push(f)
}
}
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
}

/*
* <footer> ::= <token> <separator> *<whitespace> <value> <newline>?
*/
function footer (scanner) {
const start = scanner.position()
const node = {
type: 'footer',
children: []
}
const node = scanner.enter('footer', [])
// <token>
const t = token(scanner)
if (t instanceof Error) {
Expand Down Expand Up @@ -238,8 +204,7 @@ function footer (scanner) {
if (isNewline(scanner.peek())) {
scanner.next()
}
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
}

/*
Expand All @@ -248,20 +213,14 @@ function footer (scanner) {
* | <type>
*/
function token (scanner) {
const node = {
type: 'token',
children: []
}

const node = scanner.enter('token', [])
// "BREAKING CHANGE"
const start = scanner.position()
const b = breakingChange(scanner)
if (b instanceof Error) {
scanner.rewind(start)
scanner.abort(node)
} else {
node.children.push(b)
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
}

// <type>
Expand All @@ -279,7 +238,9 @@ function token (scanner) {
} else {
node.children.push(s)
}
if (scanner.peek() !== ')') return invalidToken(scanner, [')'])
if (scanner.peek() !== ')') {
return scanner.abort(node, [')'])
}
scanner.next()
}
// ["!"]
Expand All @@ -288,29 +249,23 @@ function token (scanner) {
node.children.push(b)
}
}
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
}

/*
* <breaking-change> ::= "!" | "BREAKING CHANGE"
*/
function breakingChange (scanner) {
const start = scanner.position()
const node = {
type: 'breaking-change',
value: ''
}
const node = scanner.enter('breaking-change', '')
if (scanner.peek() === '!') {
node.value = scanner.next()
} else if (scanner.peekLiteral('BREAKING CHANGE')) {
node.value = scanner.next('BREAKING CHANGE'.length)
}
if (node.value === '') {
return invalidToken(scanner, ['BREAKING CHANGE'])
return scanner.abort(node, ['BREAKING CHANGE'])
} else {
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
}
}

Expand All @@ -319,66 +274,49 @@ function breakingChange (scanner) {
* | <text>
*/
function value (scanner) {
const start = scanner.position()
const node = {
type: 'value',
children: []
}
const node = scanner.enter('value', [])
node.children.push(text(scanner))
let c
// 1*<continuation>
while (!((c = continuation(scanner)) instanceof Error)) {
node.children.push(c)
}
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
}

/*
* <newline> <whitespace> <text>
*/
function continuation (scanner) {
const node = {
type: 'continuation',
children: []
}
const start = scanner.position()
const node = scanner.enter('continuation', [])
if (isNewline(scanner.peek())) {
scanner.next()
if (isWhitespace(scanner.peek())) {
scanner.next()
node.children.push(text(scanner))
} else {
scanner.rewind(start)
return invalidToken(scanner, ['continuation'])
return scanner.abort(node)
}
} else {
return invalidToken(scanner, ['continuation'])
return scanner.abort(node)
}
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
}

/*
* <separator> ::= ": " | " #"
*/
function separator (scanner) {
const start = scanner.position()
const node = {
type: 'separator',
value: ''
}

const node = scanner.enter('separator', '')
// ': '
if (scanner.peek() === ':') {
scanner.next()
if (scanner.peek() === ' ') {
node.value = ': '
scanner.next()
node.position = { start, end: scanner.position() }
return node
return scanner.exit(node)
} else {
return invalidToken(scanner, ['separator'])
return scanner.abort(node)
}
}

Expand All @@ -388,25 +326,13 @@ function separator (scanner) {
if (scanner.peek() === '#') {
scanner.next()
node.value = ' #'
node.position = { start, end: scanner.position() }
return scanner.exit(node)
} else {
scanner.rewind(start)
return invalidToken(scanner, ['separator'])
return scanner.abort(node)
}
} else {
return invalidToken(scanner, ['separator'])
}
return node
}

function invalidToken (scanner, expected) {
const validTokens = expected.filter(Boolean).join(', ')
if (scanner.eof()) {
return Error(`unexpected token EOF valid tokens [${validTokens}]`)
} else {
const pos = scanner.position()
return Error(`unexpected token '${scanner.peek()}' at position ${pos.line}:${pos.column} valid tokens [${validTokens}]`)
}
return scanner.abort(node)
}

module.exports = message
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