unified setting higlighting range for errors

Sources/Errors.swift

@@ -32,18 +32,15 @@ public struct TemplateSyntaxError : Error, Equatable, CustomStringConvertible {
   }
   
   static func description(reason: String, lexeme: Lexeme?, template: Template?) -> String {
-    if let template = template, let range = lexeme?.range {
-      let templateName = template.name.map({ "\($0):" }) ?? ""
-      let tokenContent = template.templateString.substring(with: range)
-      let line = template.templateString.rangeLine(range)
-      let highlight = "\(String(Array(repeating: " ", count: line.offset)))^\(String(Array(repeating: "~", count: max(tokenContent.length - 1, 0))))"
-      
-      return "\(templateName)\(line.number):\(line.offset): error: \(reason)\n"
-        + "\(line.content)\n"
-        + "\(highlight)\n"
-    } else {
-      return reason
-    }
+    guard let template = template, let lexeme = lexeme else { return reason }
+    let templateName = template.name.map({ "\($0):" }) ?? ""
+    let range = template.templateString.range(of: lexeme.contents, range: lexeme.range) ?? lexeme.range
+    let line = template.templateString.rangeLine(range)
+    let highlight = "\(String(Array(repeating: " ", count: line.offset)))^\(String(Array(repeating: "~", count: max(lexeme.contents.length - 1, 0))))"
+
+    return "\(templateName)\(line.number):\(line.offset): error: \(reason)\n"
+      + "\(line.content)\n"
+      + "\(highlight)\n"
   }
 
   init(reason: String, lexeme: Lexeme? = nil, template: Template? = nil, parentError: Error? = nil) {

Sources/Lexer.swift

@@ -77,6 +77,7 @@ struct Lexer {
 }
 
 protocol Lexeme {
+  var contents: String { get }
   var range: Range<String.Index> { get }
 }
 

Sources/Node.swift

@@ -15,13 +15,9 @@ public func renderNodes(_ nodes:[NodeType], _ context:Context) throws -> String
     do {
       return try $0.render(context)
     } catch {
-      if var syntaxError = error as? TemplateSyntaxError, syntaxError.lexeme == nil, let token = $0.token {
-        if let contentsRange = context.environment.template?.templateString.range(of: token.contents, range: token.range) {
-          syntaxError.lexeme = Token.block(value: token.contents, at: contentsRange)
-        } else {
-          syntaxError.lexeme = token
-        }
-        throw syntaxError
+      if var error = error as? TemplateSyntaxError {
+        error.lexeme = error.lexeme ?? $0.token
+        throw error
       } else {
         throw error
       }

Tests/StencilTests/EnvironmentSpec.swift

@@ -41,41 +41,25 @@ func testEnvironment() {
     
     $0.it("reports syntax error on invalid for tag syntax") {
       let template: Template = "Hello {% for name in %}{{ name }}, {% endfor %}!"
-      let error = expectedSyntaxError(
-        token: "{% for name in %}",
-        template: template,
-        description: "'for' statements should use the following syntax 'for x in y where condition'."
-      )
+      let error = expectedSyntaxError(token: "for name in", template: template, description: "'for' statements should use the following syntax 'for x in y where condition'.")
       try expect(try environment.renderTemplate(string: template.templateString, context:["names": ["Bob", "Alice"]])).toThrow(error)
     }
     
     $0.it("reports syntax error on missing endfor") {
       let template: Template = "{% for name in names %}{{ name }}"
-      let error = expectedSyntaxError(
-        token: "{% for name in names %}",
-        template: template,
-        description: "`endfor` was not found."
-      )
+      let error = expectedSyntaxError(token: "for name in names", template: template, description: "`endfor` was not found.")
       try expect(try environment.renderTemplate(string: template.templateString, context: ["names": ["Bob", "Alice"]])).toThrow(error)
     }
     
     $0.it("reports syntax error on unknown tag") {
       let template: Template = "{% for name in names %}{{ name }}{% end %}"
-      let error = expectedSyntaxError(
-        token: "{% end %}",
-        template: template,
-        description: "Unknown template tag 'end'"
-      )
+      let error = expectedSyntaxError(token: "end", template: template, description: "Unknown template tag 'end'")
       try expect(try environment.renderTemplate(string: template.templateString, context: ["names": ["Bob", "Alice"]])).toThrow(error)
     }
     
     $0.context("given unknown filter") {
       func expectedFilterError(token: String, template: Template) -> TemplateSyntaxError {
-        return expectedSyntaxError(
-          token: token,
-          template: template,
-          description: "Unknown filter 'unknown'"
-        )
+        return expectedSyntaxError(token: token, template: template, description: "Unknown filter 'unknown'")
       }
       
       $0.it("reports syntax error in for tag") {
@@ -110,7 +94,7 @@ func testEnvironment() {
       
       $0.it("reports syntax error in filter tag") {
         let template: Template = "{% filter unknown %}Text{% endfilter %}"
-        let error = expectedFilterError(token: "{% filter unknown %}", template: template)
+        let error = expectedFilterError(token: "filter unknown", template: template)
         try expect(try environment.renderTemplate(string: template.templateString, context: [:])).toThrow(error)
       }
       
@@ -228,7 +212,6 @@ func testEnvironment() {
         var error = expectedSyntaxError(token: "include \"invalid-include.html\"", template: template, description: "Unknown filter 'unknown'")
         error.parentError = parentError
         
-
         try expect(environment.renderTemplate(string: template.templateString, context: ["target": "World"])).toThrow(error)
       }
       
@@ -297,7 +280,7 @@ func testEnvironment() {
         
         let template = Template.init(templateString: "{% extends \"base.html\" %}\n" +
           "{% block body %}Child {{ target|unknown }}{% endblock %}", environment: environment, name: nil)
-        let error = expectedSyntaxError(token: "{{ target|unknown }}", template: template, description: "filter error")
+        let error = expectedSyntaxError(token: "target|unknown", template: template, description: "filter error")
         
         try expect(environment.render(template: template, context: ["target": "World"])).toThrow(error)
       }