Feature: Guards and where

lib/astupdate.js

@@ -70,9 +70,9 @@ const formMultiPatternAst = (funcdecl, patterndecls) => {
 
 const isArrowFuncDecl = (decl) => {
   const declarations = decl.declarations
-
   if (
     declarations !== undefined &&
+    declarations[0].init &&
     declarations[0].init.type === 'ArrowFunctionExpression'
   ) { return true }
   return false

lib/basicParsers.js

@@ -5,6 +5,7 @@ const estemplate = require('./estemplate')
 const {
   maybe,
   isLanguageConstruct,
+  isReservedFnCall,
   isStaticIOMethod,
   isIOMethod,
   isDOMmethod,
@@ -33,6 +34,8 @@ const openParensRegex = () => /^(\()((.|\n)*)$/
 const closeParensRegex = () => /^(\))((.|\n)*)$/
 const commaRegex = () => /^(,)((.|\n)*)$/
 const colonRegex = () => /^(:)((.|\n)*)$/
+const vBarRegex = () => /^(\|\s+)((.|\n)*)$/
+const otherwiseRegex = () => /^(otherwise)((.|\n)*)$/
 const singleLineCommentRegex = () => /^((\/\/)(.*)(?=\n|))((.|\n)*)$/
 const multiLineCommentRegex = () =>
   /^((\/\*)((.|\n)*?)(\*\/))((.|\n)*)$/
@@ -50,6 +53,7 @@ const dotRegex = () => /^(\.)((.|\n)*)$/
 const ifRegex = () => /^(if\s+)((.|\n)*)$/
 const thenRegex = () => /^(then\s+)((.|\n)*)$/
 const elseRegex = () => /^(else\s+)((.|\n)*)$/
+const whereRegex = () => /^(where\s+)((.|\n)*)$/
 const doRegex = () => /^(do)((.|\n)*)$/
 const returnKeywordRegex = () => /^(return)((.|\n)*)$/
 const includeKeywordRegex = () => /^(include)((.|\n)*)$/
@@ -84,6 +88,8 @@ const ifParser = (input) => parser.regex(ifRegex)(input)
 const thenParser = (input) => parser.regex(thenRegex)(input)
 const elseParser = (input) => parser.regex(elseRegex)(input)
 
+const whereParser = (input) => parser.regex(whereRegex)(input)
+
 const doParser = (input) => parser.regex(doRegex)(input)
 
 const returnKeywordParser = (input) =>
@@ -119,6 +125,17 @@ const nonReservedIdParser = (input) =>
       : [estemplate.identifier(name), rest]
   )
 
+const nonReservedIdFnCallParser = (input) =>
+  maybe(idParser(input), (name, rest) =>
+    isLanguageConstruct(name) ||
+    isReservedFnCall(name) ||
+    isStaticIOMethod(name) ||
+    isIOMethod(name) ||
+    isDOMmethod(name)
+      ? null
+      : [estemplate.identifier(name), rest]
+  )
+
 const identifierParser = (input) =>
   maybe(idParser(input), (name, rest) => [
     estemplate.identifier(name),
@@ -222,6 +239,14 @@ const colonParser = (input) =>
     rest
   ])
 
+const vBarParser = (input) =>
+  maybe(parser.regex(vBarRegex)(input), (bar, rest) => [
+    bar,
+    rest
+  ])
+
+const otherwiseParser = (input) => parser.regex(otherwiseRegex)(input)
+
 const singleLineCommentParser = (input) =>
   maybe(singleLineCommentRegex().exec(input.str), (...vals) => {
     const [, , , val, rest] = vals
@@ -319,6 +344,7 @@ module.exports = {
   maybeNewLineAndIndent,
   numberParser,
   nonReservedIdParser,
+  nonReservedIdFnCallParser,
   identifierParser,
   domMethodParser,
   ioFuncNameParser,
@@ -335,6 +361,8 @@ module.exports = {
   closeSquareBracketParser,
   commaParser,
   colonParser,
+  vBarParser,
+  otherwiseParser,
   singleLineCommentParser,
   multiLineCommentParser,
   binaryOperatorParser,
@@ -347,6 +375,7 @@ module.exports = {
   ifParser,
   thenParser,
   elseParser,
+  whereParser,
   doParser,
   equalSignParser,
   slashParser,

lib/estemplate.js

@@ -160,14 +160,15 @@ estemplate.printexpression = (args) => ({
   sType: 'IO'
 })
 
-estemplate.fnCall = (val, args) =>
-  val.name === 'print'
-    ? estemplate.printexpression(args)
-    : {
-        type: 'CallExpression',
-        callee: extractExpr(val),
-        arguments: args.map(extractExpr)
-      }
+estemplate.reservedCalls = {
+  print: (args) => estemplate.printexpression(args)
+}
+
+estemplate.fnCall = (val, args) => ({
+  type: 'CallExpression',
+  callee: extractExpr(val),
+  arguments: args.map(extractExpr)
+})
 
 estemplate.lambda = (params, body) => ({
   type: 'ExpressionStatement',
@@ -220,12 +221,14 @@ estemplate.ifthenelse = (condition, result1, result2) => ({
   }
 })
 
-estemplate.ifStmt = (predicate, consequent) => ({
+estemplate.ifStmt = (predicate, consequent, isReturn = false) => ({
   type: 'IfStatement',
   test: predicate,
   consequent: {
     type: 'BlockStatement',
-    body: [consequent, estemplate.returnStmt(null)]
+    body: isReturn
+      ? [estemplate.returnStmt(consequent)]
+      : [consequent, estemplate.returnStmt(null)]
   },
   alternate: null
 })

lib/languageConstructs.js

@@ -18,10 +18,17 @@ const languageConstructs = {
   false: true,
   null: true,
   do: true,
-  console: true,
   return: true,
   delete: true,
-  defineProp: true
+  defineProp: true,
+  otherwise: true
 }
 
-module.exports = languageConstructs
+const reservedFnCalls = {
+  print: true
+}
+
+module.exports = {
+  languageConstructs,
+  reservedFnCalls
+}