inital vesion of recast working

src/lang/abstractSyntaxTree.ts

@@ -123,7 +123,7 @@ function makeExpressionStatement(
   }
 }
 
-interface CallExpression extends GeneralStatement {
+export interface CallExpression extends GeneralStatement {
   type: 'CallExpression'
   callee: Identifier
   arguments: Value[]
@@ -244,7 +244,7 @@ function makeVariableDeclaration(
   }
 }
 
-type Value =
+export type Value =
   | Literal
   | Identifier
   | BinaryExpression
@@ -371,7 +371,7 @@ export type BinaryPart = Literal | Identifier
 // | LogicalExpression
 // | ConditionalExpression
 
-interface Literal extends GeneralStatement {
+export interface Literal extends GeneralStatement {
   type: 'Literal'
   value: string | number | boolean | null
   raw: string
@@ -459,7 +459,7 @@ function makeBinaryExpression(
   }
 }
 
-interface SketchExpression extends GeneralStatement {
+export interface SketchExpression extends GeneralStatement {
   type: 'SketchExpression'
   body: BlockStatement
 }
@@ -483,7 +483,7 @@ function makeSketchExpression(
   }
 }
 
-interface FunctionExpression extends GeneralStatement {
+export interface FunctionExpression extends GeneralStatement {
   type: 'FunctionExpression'
   id: Identifier | null
   params: Identifier[]

src/lang/recast.test.ts

@@ -1,8 +1,7 @@
 import { recast } from './recast'
-import { Program } from './abstractSyntaxTree'
-import { abstractSyntaxTree } from './abstractSyntaxTree'
-import { lexer } from './tokeniser'
-import { Token } from './tokeniser'
+import { Program, abstractSyntaxTree } from './abstractSyntaxTree'
+import { lexer, Token } from './tokeniser'
+import fs from 'node:fs'
 
 describe('recast', () => {
   it('recasts a simple program', () => {
@@ -26,6 +25,56 @@ describe('recast', () => {
     const { ast: ast2 } = code2ast(codeWithOtherQuotes)
     expect(recast(ast2)).toBe(codeWithOtherQuotes)
   })
+  it('test assigning two variables, the second summing with the first', () => {
+    const code = `const myVar = 5
+const newVar = myVar + 1`
+    const { ast } = code2ast(code)
+    const recasted = recast(ast)
+    expect(recasted).toBe(code)
+  })
+  it('test assigning a var by cont concatenating two strings string', () => {
+    const code = fs.readFileSync(
+      './src/lang/testExamples/variableDeclaration.cado',
+      'utf-8'
+    )
+    const { ast } = code2ast(code)
+    const recasted = recast(ast)
+    expect(recasted).toBe(code.trim())
+  })
+  it('test with function call', () => {
+    const code = `
+const myVar = "hello"
+log(5, myVar)`
+    const { ast } = code2ast(code)
+    const recasted = recast(ast)
+    expect(recasted).toBe(code.trim())
+  })
+  it('function declaration with call', () => {
+    const code =
+      [
+        'fn funcN = (a, b) => {',
+        '  return a + b',
+        '}',
+        'const theVar = 60',
+        'const magicNum = funcN(9, theVar)',
+      ].join('\n')
+    const { ast } = code2ast(code)
+    const recasted = recast(ast)
+    expect(recasted).toBe(code.trim())
+  })
+  it('sketch declaration', () => {
+    let code = `sketch mySketch {
+  path myPath = lineTo(0, 1)
+  lineTo(1, 1)
+  path rightPath = lineTo(1, 0)
+  close()
+}
+show(mySketch)
+`
+    const { ast } = code2ast(code)
+    const recasted = recast(ast)
+    expect(recasted).toBe(code.trim())
+  })
 })
 
 // helpers

src/lang/recast.ts

@@ -1,26 +1,58 @@
-import { Program, BinaryExpression, BinaryPart } from './abstractSyntaxTree'
+import {
+  Program,
+  BinaryExpression,
+  BinaryPart,
+  Literal,
+  CallExpression,
+  Value,
+  FunctionExpression,
+  SketchExpression,
+} from './abstractSyntaxTree'
 
-export function recast(ast: Program, previousWrittenCode = ''): string {
+export function recast(
+  ast: Program,
+  previousWrittenCode = '',
+  indentation = ''
+): string {
   return ast.body
     .map((statement) => {
       if (statement.type === 'ExpressionStatement') {
         if (statement.expression.type === 'BinaryExpression') {
-          return recastBinaryExpression(statement.expression)
+          return indentation + recastBinaryExpression(statement.expression)
+        } else if (statement.expression.type === 'CallExpression') {
+          return indentation + recastCallExpression(statement.expression)
         }
       } else if (statement.type === 'VariableDeclaration') {
         return statement.declarations
           .map((declaration) => {
             if (declaration.init.type === 'BinaryExpression') {
-              return `${statement.kind} ${
+              return `${indentation}${statement.kind} ${
                 declaration.id.name
               } = ${recastBinaryExpression(declaration.init)}`
             } else if (declaration.init.type === 'Literal') {
-              return `${statement.kind} ${declaration.id.name} = ${declaration.init.value}`
+              return `${indentation}${statement.kind} ${
+                declaration.id.name
+              } = ${recastLiteral(declaration.init)}`
+            } else if (declaration.init.type === 'FunctionExpression') {
+              return `${indentation}${statement.kind} ${
+                declaration.id.name
+              } = ${recastFunction(declaration.init)}`
+            } else if (declaration.init.type === 'CallExpression') {
+              return `${indentation}${statement.kind} ${
+                declaration.id.name
+              } = ${recastCallExpression(declaration.init)}`
+            } else if (declaration.init.type === 'SketchExpression') {
+              return `${indentation}${statement.kind} ${
+                declaration.id.name
+              } ${recastSketchExpression(declaration.init, indentation)}`
             }
             return ''
           })
           .join('')
+      } else if (statement.type === 'ReturnStatement') {
+        return `${indentation}return ${recastArgument(statement.argument)}`
       }
+
       return statement.type
     })
     .join('\n')
@@ -34,13 +66,53 @@ function recastBinaryExpression(expression: BinaryExpression): string {
 
 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)
+    return recastLiteral(part)
   } else if (part.type === 'Identifier') {
     return part.name
   }
   throw new Error(`Cannot recast ${part}`)
 }
+
+function recastLiteral(literal: Literal): string {
+  if (typeof literal.value === 'string') {
+    const quote = literal.raw.trim().startsWith('"') ? '"' : "'"
+    return `${quote}${literal.value}${quote}`
+  }
+  return String(literal?.value)
+}
+
+function recastCallExpression(expression: CallExpression): string {
+  return `${expression.callee.name}(${expression.arguments
+    .map(recastArgument)
+    .join(', ')})`
+}
+
+function recastArgument(argument: Value): string {
+  if (argument.type === 'Literal') {
+    return recastLiteral(argument)
+  } else if (argument.type === 'Identifier') {
+    return argument.name
+  } else if (argument.type === 'BinaryExpression') {
+    return recastBinaryExpression(argument)
+  } else if (argument.type === 'CallExpression') {
+    return recastCallExpression(argument)
+  } else if (argument.type === 'FunctionExpression') {
+    return recastFunction(argument)
+  }
+  throw new Error(`Cannot recast ${argument}`)
+}
+
+function recastFunction(expression: FunctionExpression): string {
+  return `(${expression.params.map((param) => param.name).join(', ')}) => {
+  ${recast(expression.body)}
+}`
+}
+
+function recastSketchExpression(
+  expression: SketchExpression,
+  indentation: string
+): string {
+  return `{
+${recast(expression.body, '',  indentation + '  ')}
+}`
+}