src/utils.js

   1 const path = require('path');
   2
   3 exports.PscError = class PscError extends Error {
   4   constructor(message, modules) {
   5     super(message);
   6     this.modules = modules;
   7     this.isPscError = true;
   8   }
   9
  10   static get name() {
  11     return 'PscError';
  12   }
  13 };
  14
  15 const repeat = (value, times) =>
  16   times <= 0 ? [] : [value, ...repeat(value, times - 1)];
  17 const diffPursModuleNames = (from, target, parts) => {
  18   if (!from.length) return parts.concat(target);
  19   if (!target.length) return parts.concat(repeat('..', from.length));
  20   const [head_from, ...tail_from] = from;
  21   const [head_target, ...tail_target] = target;
  22   return head_from === head_target
  23     ? diffPursModuleNames(tail_from, tail_target, parts)
  24     : parts.concat(repeat('..', from.length), target);
  25 };
  26
  27 const normalizeRewriteRuleDest = ({ dest, moduleName }) =>
  28   typeof dest === 'function' ? dest(moduleName) : dest;
  29 const rewrite = ({ rules, moduleName }) => {
  30   const moduleNameParts = moduleName.split('.')
  31   for (const [rule, dest] of Object.entries(rules)) {
  32     const ruleParts = rule.split('.');
  33     const matched = ruleParts.every((part, i) =>
  34       part === '*' || part === moduleNameParts[i]);
  35     if (!matched) continue;
  36     const rest = moduleNameParts.slice(ruleParts.length);
  37     const base = normalizeRewriteRuleDest({ dest, moduleName });
  38     return `${path.join(base, ...rest)}.purs`;
  39   }
  40 };
  41
  42 exports.resolvePursModule = ({ baseModulePath, baseModuleName, rewriteRules, targetModuleName }) => {
  43   const rewrittenModulePath = rewrite({ rules: rewriteRules, moduleName: targetModuleName });
  44   if (rewrittenModulePath) return rewrittenModulePath;
  45   const parts = diffPursModuleNames(
  46     baseModuleName.split('.'),
  47     targetModuleName.split('.'),
  48     []);
  49   return parts.length
  50     ? path.resolve(baseModulePath,
  51       `${path.join(...parts)}.purs`)
  52     : baseModulePath;
  53 };
  54
  55 exports.resolveForeignModule = pursModulePath =>
  56   path.join(path.dirname(pursModulePath),
  57     path.basename(pursModulePath, path.extname(pursModulePath)) + '.js');