Error location

Public/css/highlight.css

@@ -85,6 +85,10 @@
   color: #c0c;
 }
 
+.exp-error {
+  background: #d22;
+}
+
 span.match-char {
   background: rgba(112, 176, 224, 0.5);
   color: #101112;

Public/js/app.js

@@ -227,6 +227,10 @@ export class App {
 
   onExpressionFieldChange() {
     if (!this.expressionField.value) {
+      this.expressionField.tokens = [];
+      this.expressionField.error = null;
+      this.dslView.value = "";
+      this.dslView.error = null;
       this.updateMatchCount(0, "match-count");
       return;
     }
@@ -349,13 +353,35 @@ export class App {
         } else {
           this.expressionField.tokens = [];
         }
-        this.expressionField.error = response.error;
+        if (response.error) {
+          try {
+            const error = JSON.parse(response.error);
+            if (error) {
+              this.expressionField.error = error;
+            }
+          } catch (e) {
+            this.expressionField.error = response.error;
+          }
+        } else {
+          this.expressionField.error = null;
+        }
         break;
       case "convertToDSL":
         if (response.result) {
           this.dslView.value = JSON.parse(response.result);
         }
-        this.dslView.error = response.error;
+        if (response.error) {
+          try {
+            const error = JSON.parse(response.error);
+            if (error) {
+              this.dslView.error = error;
+            }
+          } catch (e) {
+            this.dslView.error = response.error;
+          }
+        } else {
+          this.dslView.error = null;
+        }
         break;
       case "match":
         if (response.result) {

Public/js/views/dsl_view.js

@@ -16,7 +16,7 @@ export class DSLView extends EventDispatcher {
   }
 
   set value(val) {
-    this.editor.setValue(val || this.defaultText);
+    this.editor.setValue(val);
   }
 
   set error(error) {
@@ -32,14 +32,26 @@ export class DSLView extends EventDispatcher {
       if (!error) {
         return;
       }
-
-      widgets.push(
-        editor.addLineWidget(0, ErrorMessage.create(error), {
-          coverGutter: false,
-          noHScroll: true,
-          above: true,
-        })
-      );
+      if (typeof error === "string" && error instanceof String) {
+        widgets.push(
+          editor.addLineWidget(0, ErrorMessage.create(error), {
+            coverGutter: false,
+            noHScroll: true,
+            above: true,
+          })
+        );
+      } else {
+        for (const e of error) {
+          const message = ErrorMessage.create(e.message);
+          widgets.push(
+            editor.addLineWidget(0, message, {
+              coverGutter: false,
+              noHScroll: true,
+              above: true,
+            })
+          );
+        }
+      }
     });
   }
 

Public/js/views/expression_field.js

@@ -30,17 +30,34 @@ export class ExpressionField extends EventDispatcher {
 
   set error(error) {
     if (error) {
-      const content = Utils.htmlSafe(error);
-      this.errorMessageTooltip.setContent(
-        `<span class="fw-bolder text-danger">Parse Error:</span> ${content}`
-      );
+      let message = "";
+      if (typeof error === "string" && error instanceof String) {
+        const errorMessage = Utils.htmlSafe(error);
+        message = `<span class="fw-bolder text-danger">Parse Error:</span> ${errorMessage}`;
+      } else {
+        message = error
+          .map((e) => {
+            const errorMessage = Utils.htmlSafe(e.message);
+            return `<span class="fw-bolder text-danger">${e.behavior}:</span> ${errorMessage}`;
+          })
+          .join("<br>");
+        this.highlighter.drawError(error);
+      }
+      this.errorMessageTooltip.setContent(message);
       document
         .getElementById("expression-field-error")
         .classList.remove("d-none");
     } else {
       this.errorMessageTooltip.setContent("");
       document.getElementById("expression-field-error").classList.add("d-none");
+      this.highlighter.clearError();
     }
+
+    tippy(".exp-error", {
+      allowHTML: true,
+      animation: false,
+      placement: "bottom",
+    });
   }
 
   init(container) {
@@ -85,6 +102,9 @@ export class ExpressionField extends EventDispatcher {
       ...tooltipProps,
       onShow: (instance) => {
         const index = instance.reference.dataset.tokenIndex;
+        if (index === undefined) {
+          return false;
+        }
         const token = this.expressionTokens[index];
         this.onHover(token, instance);
         return false;

Public/js/views/expression_highlighter.js

@@ -10,6 +10,7 @@ export default class ExpressionHighlighter extends EventDispatcher {
     this.editor = editor;
     this.activeMarks = [];
     this.hoverMarks = [];
+    this.widgets = [];
   }
 
   draw(tokens) {
@@ -60,13 +61,52 @@ export default class ExpressionHighlighter extends EventDispatcher {
     });
   }
 
+  drawError(errors) {
+    this.clearError();
+
+    const pre = ExpressionHighlighter.CSS_PREFIX;
+    const editor = this.editor;
+    editor.operation(() => {
+      for (const error of errors) {
+        const location = Editor.calcRangePos(
+          this.editor,
+          error.location.start,
+          error.location.end - error.location.start
+        );
+        const widget = document.createElement("span");
+        widget.className = `${pre}-error`;
+
+        widget.style.height = `2px`;
+        widget.style.zIndex = "10";
+        widget.setAttribute("data-tippy-content", error.message);
+
+        editor.addWidget(location.startPos, widget);
+        const startCoords = editor.charCoords(location.startPos, "local");
+        const endCoords = editor.charCoords(location.endPos, "local");
+        widget.style.left = `${startCoords.left + 1}px`;
+        widget.style.top = `${startCoords.bottom}px`;
+        widget.style.width = `${endCoords.left - startCoords.left - 2}px`;
+
+        this.widgets.push(widget);
+      }
+    });
+  }
+
   clear() {
     this.editor.operation(() => {
-      let marks = this.activeMarks;
-      for (var i = 0, l = marks.length; i < l; i++) {
-        marks[i].clear();
+      for (const mark of this.activeMarks) {
+        mark.clear();
+      }
+      this.activeMarks.length = 0;
+    });
+  }
+
+  clearError() {
+    this.editor.operation(() => {
+      for (const widget of this.widgets) {
+        widget.parentNode.removeChild(widget);
       }
-      marks.length = 0;
+      this.widgets.length = 0;
     });
   }
 
@@ -77,9 +117,7 @@ export default class ExpressionHighlighter extends EventDispatcher {
       return;
     }
 
-    while (this.hoverMarks.length) {
-      this.hoverMarks.pop().clear();
-    }
+    this.clearHover();
 
     if (selection) {
       this.drawBorder(selection, "selected");
@@ -119,9 +157,12 @@ export default class ExpressionHighlighter extends EventDispatcher {
   }
 
   clearHover() {
-    while (this.hoverMarks.length) {
-      this.hoverMarks.pop().clear();
-    }
+    this.editor.operation(() => {
+      for (const mark of this.hoverMarks) {
+        mark.clear();
+      }
+      this.hoverMarks.length = 0;
+    });
   }
 }
 

Sources/DSLConverter/DSLConverter.swift

@@ -3,9 +3,13 @@ import Foundation
 @testable @_spi(RegexBuilder) import _StringProcessing
 @testable @_spi(PatternConverter) import _StringProcessing
 
-struct DSLConverter {
+class DSLConverter {
+  private(set) var diagnostics: Diagnostics?
+
   func convert(_ pattern: String, matchingOptions: [String] = []) throws -> String {
-    let ast = try _RegexParser.parse(pattern, .traditional)
+    let ast = _RegexParser.parseWithRecovery(pattern, .traditional)
+    diagnostics = ast.diags
+
     var builderDSL = renderAsBuilderDSL(ast: ast)
     if builderDSL.last == "\n" {
       builderDSL = String(builderDSL.dropLast())

Sources/DSLConverter/Main.swift

@@ -14,8 +14,34 @@ struct Main {
 
       let data = try JSONEncoder().encode(builderDSL)
       print(String(data: data, encoding: .utf8) ?? "")
+
+      if let diagnostics = converter.diagnostics {
+        let errors = diagnostics.diags.map {
+          let location = $0.location
+          let (start, end) = (location.start, location.end)
+
+          let behavior = switch $0.behavior {
+          case .fatalError:
+            "Fatal Error"
+          case .error:
+            "Error"
+          case .warning:
+            "Warning"
+          }
+          return LocatedMessage(
+            behavior: behavior,
+            message: $0.message,
+            location: Location(
+              start: start.utf16Offset(in: pattern), end: end.utf16Offset(in: pattern)
+            )
+          )
+        }
+
+        let data = try JSONEncoder().encode(errors)
+        print(String(data: data, encoding: .utf8) ?? "", to: &standardError)
+      }
     } catch {
-      print("\(error)", to:&standardError)
+      print("\(error)", to: &standardError)
     }
   }
 }
@@ -28,3 +54,14 @@ extension FileHandle: @retroactive TextOutputStream {
     self.write(data)
   }
 }
+
+struct Location: Codable {
+  let start: Int
+  let end: Int
+}
+
+struct LocatedMessage: Codable {
+  let behavior: String
+  let message: String
+  let location: Location
+}

Sources/ExpressionParser/Main.swift

@@ -12,15 +12,37 @@ struct Main {
       var parser = ExpressionParser(pattern: pattern, matchingOptions: matchingOptions)
       parser.parse()
 
-      let data = try JSONEncoder().encode(parser.tokens)
+      let encoder = JSONEncoder()
+      let data = try encoder.encode(parser.tokens)
       print(String(data: data, encoding: .utf8) ?? "")
+
       if let diagnostics = parser.diagnostics {
-        for diag in diagnostics.diags {
-          print("\(diag.message)", to:&standardError)
+        let errors = diagnostics.diags.map {
+          let location = $0.location
+          let (start, end) = (location.start, location.end)
+
+          let behavior = switch $0.behavior {
+          case .fatalError:
+            "Fatal Error"
+          case .error:
+            "Error"
+          case .warning:
+            "Warning"
+          }
+          return LocatedMessage(
+            behavior: behavior,
+            message: $0.message,
+            location: Location(
+              start: start.utf16Offset(in: pattern), end: end.utf16Offset(in: pattern)
+            )
+          )
         }
+
+        let data = try JSONEncoder().encode(errors)
+        print(String(data: data, encoding: .utf8) ?? "", to: &standardError)
       }
     } catch {
-      print("\(error)", to:&standardError)
+      print("\(error)", to: &standardError)
     }
   }
 }
@@ -33,3 +55,9 @@ extension FileHandle: @retroactive TextOutputStream {
     self.write(data)
   }
 }
+
+struct LocatedMessage: Codable {
+  let behavior: String
+  let message: String
+  let location: Location
+}

Sources/Matcher/Main.swift

@@ -22,7 +22,7 @@ struct Main {
       let data = try JSONEncoder().encode(matches)
       print(String(data: data, encoding: .utf8) ?? "")
     } catch {
-      print("\(error)", to:&standardError)
+      print("\(error)", to: &standardError)
     }
   }
 }