Return warnings about recoverable parsing problems

Author: prantlf

.eslintrc.yml

@@ -1,3 +1,4 @@
 extends: standard
 rules:
   no-labels: off
+  no-multi-spaces: off

CHANGELOG.md

@@ -1,5 +1,17 @@
 # Changelog
 
+## 0.1.0
+
+Include a new property `warnings` in the parser output or error, which will contain an array of warnings. A warning is a mistake in the source code, which is not fatal (and will be compiled and executed properly), but which is against the modern language specification. Warn  about:
+
+* A line break in a single-line string
+* A backslash not followed by a whitespace
+* A `ifdef` or `ifndef` preprocessor directive without a name identifier following it
+* An object declared with other modifier than `public`
+* A preprocessor directive followed by non-whitespace characters
+* A semicolon following feature, function or script declaration
+* A missing line break or semicolon after an empty c-like for statement before the end keyword
+
 ## 0.0.1
 
 Initial release.

README.md

@@ -167,6 +167,7 @@ Options:
   -S|--source <type>  source type is object, script (default) or dump
   -O|--old-version    expect the old version of OScript. defaults to false
   -e|--errors-only    print only files that failed the check
+  -w|--warnings       consider warnings as failures too
   -s|--silent         suppress output
   -v|--verbose        print error stacktrace
   -p|--performance    print parsing timing

dist/index.d.ts

@@ -34,12 +34,16 @@ export type SourceType = 'object' | 'script' | 'dump'
 // ============================================================
 // Error Handling
 
-export interface ParseError extends Error {
+export interface ParseWarning extends Error {
   line?: number
   column?: number
   offset?: number
   source?: string
+}
+
+export interface ParseError extends ParseWarning {
   tokens?: Token[]
+  warnings: ParseWarning[]
 }
 
 // ============================================================
@@ -104,6 +108,7 @@ export interface TokenTypes {
   ObjRef: 16384
   LegacyAlias: 32768
   KeywordOrIdentifier: 64 | 128
+  PunctuatorOrKeyword: 32 | 64
   Literal: 256 | 512 | 1024 | 2048 | 4096 | 8182 | 16384
   NoCode: 2 | 4 | 8 | 16
 }
@@ -115,6 +120,7 @@ export interface Program extends Node {
   type: 'Program'
   body: PackageDeclaration | ScriptSource | DumpSource
   tokens?: Token[] // if tokens are enabled during parsing
+  warnings: ParseWarning[]
 }
 
 // ---------- Package

lib/bin/oslint.js

@@ -7,6 +7,7 @@ import { parseText } from 'oscript-parser'
 const { version } = JSON.parse(readFileSync(join(__dirname, '../../package.json'), 'utf-8'))
 const args = process.argv
 let errorsOnly = false
+let considerWarnings = false
 let silent = false
 let verbose = false
 let measure = false
@@ -25,6 +26,7 @@ Options:
   -S|--source <type>  source type is object, script (default) or dump
   -O|--old-version    expect the old version of OScript. defaults to false
   -e|--errors-only    print only files that failed the check
+  -w|--warnings       consider warnings as failures too
   -s|--silent         suppress output
   -v|--verbose        print error stacktrace
   -p|--performance    print parsing timing
@@ -53,6 +55,9 @@ for (let i = 2, l = args.length; i < l; ++i) {
       case 'e': case 'errors-only':
         errorsOnly = true
         continue
+      case 'w': case 'warnings':
+        considerWarnings = true
+        continue
       case 's': case 'silent':
         silent = true
         continue
@@ -113,14 +118,22 @@ function run () {
   try {
     options.sourceFile = source.name
     const start = measure && performance.now()
-    parseText(source.code, options)
+    const { warnings } = parseText(source.code, options)
     let time
     if (start) {
       const end = performance.now()
       time = ` in ${Math.round(end - start)}ms`
     } else {
       time = ''
     }
+    if (considerWarnings && warnings.length) {
+      if (!silent) {
+        for (const { message, line, column } of warnings) {
+          console.warn(`${source.name}:${line}:${column}: ${message}`)
+        }
+      }
+      process.exitCode = 1
+    }
     if (!silent && !errorsOnly) console.log(`${source.name} succeeded${time}`)
   } catch (error) {
     if (!silent) {

lib/errors.js

@@ -0,0 +1,13 @@
+const slice = Array.prototype.slice // optimize the often access
+
+// A sprintf-like implementation using `%index` placeholders (index based on 1)
+// to insert arguments to the message format.
+//
+// Example:
+//   // Unexpected function in token
+//   formatMessage('Unexpected %2 in %1.', 'token', 'function')
+
+export default function formatMessage (format) {
+  const args = slice.call(arguments, 1)
+  return format.replace(/%(\d)/g, (match, index) => '' + args[index - 1])
+}