Add AtomAppendMode (#149)

It will allow the command to completely replace the previously created formula.
ForNeVeR · Dec 3, 2019 · b65a080 · b65a080
1 parent ca598ac
commit b65a080
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Showing 4 changed files with 32 additions and 13 deletions.
diff --git a/src/WpfMath/Parsers/AtomAppendMode.cs b/src/WpfMath/Parsers/AtomAppendMode.cs
@@ -0,0 +1,8 @@
+namespace WpfMath
+{
+    internal enum AtomAppendMode
+    {
+        Add,
+        Replace
+    }
+}
diff --git a/src/WpfMath/Parsers/CommandParsers.cs b/src/WpfMath/Parsers/CommandParsers.cs
@@ -57,10 +57,13 @@ internal class CommandProcessingResult
         /// </summary>
         public int NextPosition { get; }
 
-        public CommandProcessingResult(Atom atom, int nextPosition)
+        public AtomAppendMode AppendMode { get; }
+
+        public CommandProcessingResult(Atom atom, int nextPosition, AtomAppendMode appendMode = AtomAppendMode.Add)
         {
             Atom = atom;
             NextPosition = nextPosition;
+            AppendMode = appendMode;
         }
     }
 

diff --git a/src/WpfMath/Parsers/StandardCommands.cs b/src/WpfMath/Parsers/StandardCommands.cs
@@ -49,7 +49,7 @@ public CommandProcessingResult ProcessCommand(CommandContext context)
                 var start = context.CommandNameStartPosition;
                 var atomSource = source.Segment(start, position - start);
                 var atom = new MatrixAtom(atomSource, rows, MatrixCellAlignment.Center);
-                return new CommandProcessingResult(atom, position);
+                return new CommandProcessingResult(atom, position, AtomAppendMode.Replace);
             }
 
         }

diff --git a/src/WpfMath/TexFormulaParser.cs b/src/WpfMath/TexFormulaParser.cs
@@ -383,7 +383,7 @@ private TexFormula ReadScript(
             Parse(ReadElement(value, ref position), formula.TextStyle, environment.CreateChildEnvironment());
 
         /// <remarks>May return <c>null</c> for commands that produce no atoms.</remarks>
-        private Atom ProcessCommand(
+        private (AtomAppendMode, Atom) ProcessCommand(
             TexFormula formula,
             SourceSpan value,
             ref int position,
@@ -408,7 +408,7 @@ private Atom ProcessCommand(
                             formula.TextStyle,
                             environment.CreateChildEnvironment());
                         source = value.Segment(start, position - start);
-                        return new FractionAtom(source, numeratorFormula.RootAtom, denominatorFormula.RootAtom, true);
+                        return (AtomAppendMode.Add, new FractionAtom(source, numeratorFormula.RootAtom, denominatorFormula.RootAtom, true));
                     }
                 case "left":
                     {
@@ -430,7 +430,7 @@ private Atom ProcessCommand(
 
                         var closing = internals.ClosingDelimiter;
                         source = value.Segment(start, position - start);
-                        return new FencedAtom(source, internals.Body, opening, closing);
+                        return (AtomAppendMode.Add, new FencedAtom(source, internals.Body, opening, closing));
                     }
                 case "overline":
                     {
@@ -439,7 +439,7 @@ private Atom ProcessCommand(
                             formula.TextStyle,
                             environment.CreateChildEnvironment());
                         source = value.Segment(start, position - start);
-                        return new OverlinedAtom(source, overlineFormula.RootAtom);
+                        return (AtomAppendMode.Add, new OverlinedAtom(source, overlineFormula.RootAtom));
                     }
                 case "right":
                     {
@@ -460,7 +460,7 @@ private Atom ProcessCommand(
                             throw new TexParseException($"Cannot find delimiter named {delimiter}");
 
                         closedDelimiter = true;
-                        return closing;
+                        return (AtomAppendMode.Add, closing);
                     }
                 case "sqrt":
                     {
@@ -483,7 +483,7 @@ private Atom ProcessCommand(
                             environment.CreateChildEnvironment());
 
                         source = value.Segment(start, position - start);
-                        return new Radical(source, sqrtFormula.RootAtom, degreeFormula?.RootAtom);
+                        return (AtomAppendMode.Add, new Radical(source, sqrtFormula.RootAtom, degreeFormula?.RootAtom));
                     }
                 case "color":
                 {
@@ -493,7 +493,7 @@ private Atom ProcessCommand(
                     var bodyFormula = Parse(bodyValue, formula.TextStyle, environment.CreateChildEnvironment());
                     source = value.Segment(start, position - start);
 
-                    return new StyledAtom(source, bodyFormula.RootAtom, null, new SolidColorBrush(color));
+                    return (AtomAppendMode.Add, new StyledAtom(source, bodyFormula.RootAtom, null, new SolidColorBrush(color)));
                 }
                 case "colorbox":
                 {
@@ -503,7 +503,7 @@ private Atom ProcessCommand(
                     var bodyFormula = Parse(bodyValue, formula.TextStyle, environment.CreateChildEnvironment());
                     source = value.Segment(start, position - start);
 
-                    return new StyledAtom(source, bodyFormula.RootAtom, new SolidColorBrush(color), null);
+                    return (AtomAppendMode.Add, new StyledAtom(source, bodyFormula.RootAtom, new SolidColorBrush(color), null));
                 }
                 }
 
@@ -517,7 +517,7 @@ private Atom ProcessCommand(
                         $"Incorrect parser behavior for command {command}: NextPosition = {parseResult.NextPosition}, position = {position}. Parser did not made any progress.");
 
                 position = parseResult.NextPosition;
-                return parseResult.Atom;
+                return (parseResult.AppendMode, parseResult.Atom);
             }
 
             throw new TexParseException("Invalid command.");
@@ -636,7 +636,7 @@ private void ProcessEscapeSequence(TexFormula formula,
                  || _commandRegistry.ContainsKey(command))
             {
                 // Command was found.
-                var commandAtom = ProcessCommand(
+                var (appendMode, commandAtom) = ProcessCommand(
                     formula,
                     value,
                     ref position,
@@ -658,7 +658,15 @@ private void ProcessEscapeSequence(TexFormula formula,
                             environment);
 
                     var source = new SourceSpan(formulaSource.Source, formulaSource.Start, commandAtom.Source.End);
-                    formula.Add(commandAtom, source);
+                    switch (appendMode)
+                    {
+                        case AtomAppendMode.Add:
+                            formula.Add(commandAtom, source);
+                            break;
+                        case AtomAppendMode.Replace:
+                            formula.RootAtom = commandAtom;
+                            break;
+                    }
                 }
             }
             else