Use POSIX paths on Windows systems (#1470)

Author: ianyong

src/localImports/preprocessor.ts

@@ -1,5 +1,5 @@
 import es from 'estree'
-import * as path from 'path'
+import * as posixPath from 'path/posix'
 
 import { CannotFindModuleError, CircularImportError } from '../errors/localImportErrors'
 import { parse } from '../parser/parser'
@@ -39,11 +39,11 @@ export const getImportedLocalModulePaths = (
   program: es.Program,
   currentFilePath: string
 ): Set<string> => {
-  if (!path.isAbsolute(currentFilePath)) {
+  if (!posixPath.isAbsolute(currentFilePath)) {
     throw new Error(`Current file path '${currentFilePath}' is not absolute.`)
   }
 
-  const baseFilePath = path.resolve(currentFilePath, '..')
+  const baseFilePath = posixPath.resolve(currentFilePath, '..')
   const importedLocalModuleNames: Set<string> = new Set()
   const importDeclarations = program.body.filter(isImportDeclaration)
   importDeclarations.forEach((importDeclaration: es.ImportDeclaration): void => {
@@ -52,7 +52,7 @@ export const getImportedLocalModulePaths = (
       throw new Error('Module names must be strings.')
     }
     if (!isSourceModule(modulePath)) {
-      const absoluteModulePath = path.resolve(baseFilePath, modulePath)
+      const absoluteModulePath = posixPath.resolve(baseFilePath, modulePath)
       importedLocalModuleNames.add(absoluteModulePath)
     }
   })
@@ -192,7 +192,7 @@ const preprocessFileImports = (
   // We want to operate on the entrypoint program to get the eventual
   // preprocessed program.
   const entrypointProgram = programs[entrypointFilePath]
-  const entrypointDirPath = path.resolve(entrypointFilePath, '..')
+  const entrypointDirPath = posixPath.resolve(entrypointFilePath, '..')
 
   // Create variables to hold the imported statements.
   const entrypointProgramModuleDeclarations = entrypointProgram.body.filter(isModuleDeclaration)

src/localImports/transformers/transformProgramToFunctionDeclaration.ts

@@ -1,5 +1,5 @@
 import es from 'estree'
-import * as path from 'path'
+import * as posixPath from 'path/posix'
 
 import { defaultExportLookupName } from '../../stdlib/localImport.prelude'
 import {
@@ -50,7 +50,7 @@ export const getInvokedFunctionResultVariableNameToImportSpecifiersMap = (
     // current file path to get the absolute file path of the file to
     // be imported. Since the absolute file path is guaranteed to be
     // unique, it is also the canonical file path.
-    const importFilePath = path.resolve(currentDirPath, importSource)
+    const importFilePath = posixPath.resolve(currentDirPath, importSource)
     // Even though we limit the chars that can appear in Source file
     // paths, some chars in file paths (such as '/') cannot be used
     // in function names. As such, we substitute illegal chars with
@@ -287,7 +287,7 @@ export const transformProgramToFunctionDeclaration = (
   currentFilePath: string
 ): es.FunctionDeclaration => {
   const moduleDeclarations = program.body.filter(isModuleDeclaration)
-  const currentDirPath = path.resolve(currentFilePath, '..')
+  const currentDirPath = posixPath.resolve(currentFilePath, '..')
 
   // Create variables to hold the imported statements.
   const invokedFunctionResultVariableNameToImportSpecifiersMap =