Terrace/packages/js/core/src/parser.ts
2023-02-01 21:50:29 -05:00

51 lines
1.8 KiB
TypeScript

enum LineType {
BLANK,
NORMAL,
}
export type LineData = {
line: string;
indent: string;
type: number;
level: number;
offsetHead: number;
offsetTail: number;
}
export function createLineData(line: string = '', indent: string = ' '): LineData {
return { line, indent, type: 0, level: 0, offsetHead: 0, offsetTail: 0 }
}
export function parseLine(lineData: LineData): LineData {
if ((typeof lineData !== 'object' || !lineData) || typeof lineData.type !== 'number' || typeof lineData.level !== 'number') throw new Error(`'lineData' must be an object with 'line' string, and 'type' and 'level' integer properties`)
if (typeof lineData.indent !== 'string' || lineData.indent.length === 0 || lineData.indent.length > 1) throw new Error(`'lineData.indent' must be a single-character string`)
if (typeof lineData.line !== 'string') throw new Error(`'lineData.line' must be a string`)
let type = LineType.BLANK
let level = 0
if (!lineData.line.length) {
// TODO: Not sure if this is necessary. If the previous line was a normal line, it makes the blank line a child of the normal line.
// If the previous line was a blank line, the blank line retains the same level.
if (lineData.type === LineType.NORMAL) level = lineData.level + 1
if (lineData.type === LineType.BLANK) level = lineData.level
lineData.type = type
lineData.level = level
lineData.offsetHead = 0
lineData.offsetTail = 0
} else {
type = LineType.NORMAL
while (lineData.line[level] === lineData.indent && level <= lineData.level + 1) ++level
lineData.type = type
lineData.level = level
lineData.offsetHead = level
lineData.offsetTail = level
while (lineData.line[lineData.offsetTail] && lineData.line[lineData.offsetTail] !== ' ') ++lineData.offsetTail
}
return lineData
}