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feat: Added parsing of If, While etc to JS interpreter
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@beneboy
beneboy committed Sep 2, 2019
1 parent 1fdbd1d commit 7c062d1
Showing 1 changed file with 96 additions and 22 deletions.
118 changes: 96 additions & 22 deletions ts/executor.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -28,14 +28,16 @@ import {
VariableDeclaration,
ExpressionStatement,
AssignmentExpression,
ImportDeclaration
ImportDeclaration,
WhileStatement,
DoWhileStatement,
IfStatement,
Program
} from 'meriyah/dist/estree'

// eslint-disable-next-line @typescript-eslint/no-floating-promises
main()

type ExecutableCode = CodeChunk | CodeExpression

interface StringDict {
// eslint-disable-next-line @typescript-eslint/no-explicit-any
[key: string]: any
Expand All @@ -49,6 +51,13 @@ interface CliArgs {
parameterValues: StringDict
}

interface CodeChunkExecution {
codeChunk: CodeChunk
parseResult: CodeChunkParseResult
}

type ExecutableCode = CodeChunkExecution | CodeExpression

/**
* Process argv to get the source and destination for the document being executed
*/
Expand Down Expand Up @@ -90,11 +99,8 @@ function execute(code: ExecutableCode[], parameterValues: StringDict): void {
})

code.forEach(c => {
if (isA('CodeChunk', c)) {
executeCodeChunk(c)
} else if (isA('CodeExpression', c)) {
executeCodeExpression(c)
}
if (isA('CodeExpression', c)) executeCodeExpression(c)
else executeCodeChunk(c)
})
}

Expand All @@ -106,7 +112,7 @@ function parseItem(
// eslint-disable-next-line @typescript-eslint/no-explicit-any
item: any,
parameters: Parameter[],
code: (CodeChunk | CodeExpression)[]
code: (CodeChunkExecution | CodeExpression)[]
): void {
if (isA('Entity', item) || item instanceof Object) {
if (isA('Parameter', item)) {
Expand All @@ -117,13 +123,19 @@ function parseItem(
) {
if (isA('CodeChunk', item)) {
const parseResult = parseCodeChunk(item)
parseResult.finalize()

item.imports = parseResult.imports
item.declares = parseResult.declares
item.assigns = parseResult.assigns
item.alters = parseResult.alters
item.uses = parseResult.uses
}
code.push(item)

code.push({
codeChunk: item,
parseResult: parseResult
})
} else code.push(item)
}

Object.entries(item).forEach(([, i]) => {
Expand All @@ -135,6 +147,8 @@ function parseItem(
}

class CodeChunkParseResult {
public chunkAst: Program

public imports: string[] = []

public declares: (Variable | Function)[] = []
Expand All @@ -147,16 +161,30 @@ class CodeChunkParseResult {

private seenIdentifiers: string[] = []

private possibleVariables: string[] = []

public constructor(chunkAst: Program) {
this.chunkAst = chunkAst
}

private isNameSet(name: string): boolean {
if (this.seenIdentifiers.indexOf(name) === -1) {
if (!this.seenIdentifiers.includes(name)) {
this.seenIdentifiers.push(name)
return false
}
return true
}

public addImports(n: string): void {
if (this.imports.indexOf(n) === -1) this.imports.push(n)
if (!this.imports.includes(n)) this.imports.push(n)
}

public addPossibleVariable(n: string): void {
/* If a declaration has a more complex initializer (like a ternary) then we don't know straight away if it's a
* variable or a function. So the identifier goes in here and if it wasn't computed to be a function declaration
* after parsing the rest of the code chunk, then set is as a variable.
*/
if (!this.possibleVariables.includes(n)) this.possibleVariables.push(n)
}

public addDeclares(d: Variable | Function): void {
Expand All @@ -174,6 +202,12 @@ class CodeChunkParseResult {
public addUses(n: string): void {
if (!this.isNameSet(n)) this.uses.push(n)
}

public finalize(): void {
this.possibleVariables.forEach(n => {
if (!this.seenIdentifiers.includes(n)) this.declares.push(variable(n))
})
}
}

function recurseMemberExpression(expr: MemberExpression): string | null {
Expand Down Expand Up @@ -212,11 +246,12 @@ function parseVariableDeclaration(
): void {
statement.declarations.forEach(declarator => {
if (declarator.id.type === 'Identifier') {
if (declarator.init === null) return

if (declarator.init.type === 'Literal')
if (declarator.init === null || declarator.init.type === 'Literal')
result.addDeclares(variable(declarator.id.name))
else parseStatement(result, declarator.init, declarator.id.name)
else {
result.addPossibleVariable(declarator.id.name)
parseStatement(result, declarator.init, declarator.id.name)
}
}
})
}
Expand Down Expand Up @@ -285,6 +320,26 @@ function parseImportExpression(
}
}

function parseWhileStatement(
result: CodeChunkParseResult,
statement: WhileStatement | DoWhileStatement
): void {
parseStatement(result, statement.test)

parseStatement(result, statement.body)
}

function parseIfStatement(
result: CodeChunkParseResult,
statement: IfStatement
): void {
parseStatement(result, statement.test)
parseStatement(result, statement.consequent)
if (statement.alternate !== null) {
parseStatement(result, statement.alternate)
}
}

function parseExpression(
result: CodeChunkParseResult,
statement: ExpressionStatement
Expand Down Expand Up @@ -329,6 +384,24 @@ function parseStatement(
case 'ImportDeclaration':
parseImportExpression(result, statement as ImportDeclaration)
break
case 'WhileStatement':
case 'DoWhileStatement':
// both actually have the same interface so it is OK to cast just to WhileStatement
parseWhileStatement(result, statement as WhileStatement)
break
case 'IfStatement':
case 'ConditionalExpression':
// both actually have the same interface so it is OK to cast just to IfStatement
parseIfStatement(result, statement as IfStatement)
break
case 'BlockStatement':
statement.body.forEach(subStatement => {
parseStatement(result, subStatement)
})
break
case 'EmptyStatement':
case 'Identifier':
case 'UnaryExpression':
case 'Literal':
break
default:
Expand All @@ -340,7 +413,7 @@ function parseStatement(
function parseCodeChunk(codeChunk: CodeChunk): CodeChunkParseResult {
const chunkAst = parse(codeChunk.text, { module: true })

const parseResult: CodeChunkParseResult = new CodeChunkParseResult()
const parseResult: CodeChunkParseResult = new CodeChunkParseResult(chunkAst)

chunkAst.body.forEach(statement => {
parseStatement(parseResult, statement)
Expand All @@ -365,11 +438,12 @@ function executeCodeExpression(code: CodeExpression): void {
*
* Uses `eval`, so should only be called with trusted code.
*/
function executeCodeChunk(code: CodeChunk): void {
function executeCodeChunk(code: CodeChunkExecution): void {
// eslint-disable-next-line @typescript-eslint/no-explicit-any
const outputs: any[] = []

const ast = parse(code.text, { module: true })
const ast = code.parseResult.chunkAst
const chunk = code.codeChunk

ast.body.forEach(statement => {
/*
Expand Down Expand Up @@ -403,7 +477,7 @@ function executeCodeChunk(code: CodeChunk): void {
}
})

code.outputs = outputs.filter(o => o !== undefined)
chunk.outputs = outputs.filter(o => o !== undefined)
}

/**
Expand Down Expand Up @@ -433,7 +507,7 @@ function decodeParameter(parameter: Parameter, value?: string): any {
return b === 'true' || b === 't' || b === 'yes' || b === '1'
case 'EnumSchema':
const es = parameter.schema as EnumSchema
if (es.values !== undefined && es.values.indexOf(value) === -1)
if (es.values !== undefined && !es.values.includes(value))
throw new Error(
`${value} not found in enum values for ${parameter.name}`
)
Expand Down

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