74 lines
2.2 KiB
TypeScript
74 lines
2.2 KiB
TypeScript
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import {LexInput} from '../lexer.js'
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import {ExpectedEndOfInputError, InvalidVariableNameError, UnexpectedEndOfInputError} from "../parse.js";
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export type StrLVal = { term: 'variable', name: string }
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export type StrTerm =
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{ term: 'string', value: string }
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| StrLVal
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export class ParseContext {
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constructor(
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private inputs: LexInput[],
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) {}
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assertEmpty() {
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if ( this.inputs.length ) {
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throw new ExpectedEndOfInputError(`Expected end of input. Found: ${this.inputs[0].value}`)
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}
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}
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popOptionalTerm(): StrTerm|undefined {
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if ( this.inputs.length ) return this.popTerm()
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return undefined
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}
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popTerm(): StrTerm {
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if ( !this.inputs.length ) {
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throw new UnexpectedEndOfInputError('Unexpected end of input. Expected term.');
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}
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const input = this.inputs.shift()!
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// Check if the token is a literal variable name:
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if ( !input.literal && input.value.startsWith('$') ) {
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if ( !input.value.match(/^\$[a-zA-Z0-9_]+$/) ) {
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throw new InvalidVariableNameError(`Invalid variable name: ${input.value}`)
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}
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return { term: 'variable', name: input.value }
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}
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// Otherwise, parse it as a string literal:
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return { term: 'string', value: input.value }
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}
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popLVal(): StrLVal {
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if ( !this.inputs.length ) {
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throw new UnexpectedEndOfInputError('Unexpected end of input. Expected lval.');
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}
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const input = this.inputs.shift()!
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if ( input.literal || !input.value.match(/^\$[a-zA-Z0-9_]+$/) ) {
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throw new InvalidVariableNameError(`Expected variable name. Found: ${input.value}`)
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}
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return { term: 'variable', name: input.value }
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}
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}
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export type CommandData = Record<string, unknown>
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export abstract class Command<TData extends CommandData> {
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abstract isParseCandidate(token: LexInput): boolean
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abstract attemptParse(context: ParseContext): TData
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abstract getDisplayName(): string
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protected isKeyword(token: LexInput, keyword: string): boolean {
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return !token.literal && token.value === keyword
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}
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}
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