Files
modeling-app/src/lang/recast.ts
2022-11-26 08:31:10 +11:00

47 lines
1.5 KiB
TypeScript

import { Program, BinaryExpression, BinaryPart } from './abstractSyntaxTree'
export function recast(ast: Program, previousWrittenCode = ''): string {
return ast.body
.map((statement) => {
if (statement.type === 'ExpressionStatement') {
if (statement.expression.type === 'BinaryExpression') {
return recastBinaryExpression(statement.expression)
}
} else if (statement.type === 'VariableDeclaration') {
return statement.declarations
.map((declaration) => {
if (declaration.init.type === 'BinaryExpression') {
return `${statement.kind} ${
declaration.id.name
} = ${recastBinaryExpression(declaration.init)}`
} else if (declaration.init.type === 'Literal') {
return `${statement.kind} ${declaration.id.name} = ${declaration.init.value}`
}
return ''
})
.join('')
}
return statement.type
})
.join('\n')
}
function recastBinaryExpression(expression: BinaryExpression): string {
return `${recastBinaryPart(expression.left)} ${
expression.operator
} ${recastBinaryPart(expression.right)}`
}
function recastBinaryPart(part: BinaryPart): string {
if (part.type === 'Literal') {
if (typeof part.value === 'string') {
const quote = part.raw.includes('"') ? '"' : "'"
return `${quote}${part.value}${quote}`
}
return String(part?.value)
} else if (part.type === 'Identifier') {
return part.name
}
throw new Error(`Cannot recast ${part}`)
}