A complete syntax highlighter that finds keywords, strings, and comments, and wraps them in pseudo-HTML tags for styling.

ID: 1384

See: Project: Implementing a Custom Syntax Highlighter 
				
					using uCalcSoftware;

var uc = new uCalc();
using (var t = new uCalc.Transformer()) {
   // 1. Define integer constants for our syntax categories
   var TAG_KEYWORD = 1;
   var TAG_STRING = 2;
   var TAG_COMMENT = 3;

   // 2. Define the transformation rules and tag them
   t.Pattern("{ if | else | for | while }").SetTag(TAG_KEYWORD);
   t.Pattern("{@String}").SetTag(TAG_STRING);
   t.Pattern("// {text}").SetTag(TAG_COMMENT);

   // 3. Set the source code and run the find operation
   string sourceCode = """
for (i=0; i<10; i++) {
  s = "hello";
  // comment
}
""";
   t.Text = sourceCode;
   t.Find();

   // 4. Build the highlighted output string
   string highlightedOutput = "";
   var lastPos = 0;

   foreach(var match in t.Matches) {
      // Append the plain text between the last match and this one
      highlightedOutput = highlightedOutput + sourceCode.Substring(lastPos, match.StartPosition - lastPos);

      // Get the tag and wrap the matched text accordingly
      var tag = match.Rule.Tag;
      if (tag == TAG_KEYWORD) {
         highlightedOutput = highlightedOutput + "<keyword>" + match.Text + "</keyword>";
      } else if (tag == TAG_STRING) {
         highlightedOutput = highlightedOutput + "<string>" + match.Text + "</string>";
      } else if (tag == TAG_COMMENT) {
         highlightedOutput = highlightedOutput + "<comment>" + match.Text + "</comment>";
      } else {
         highlightedOutput = highlightedOutput + match.Text; // No tag, append as-is
      }

      // Update the position for the next iteration
      lastPos = match.EndPosition;
   }

   // Append any remaining text after the last match
   highlightedOutput = highlightedOutput + sourceCode.Substring(lastPos);

   Console.WriteLine(highlightedOutput);
}
				
			
<keyword>for</keyword> (i=0; i<10; i++) {
  s = <string>"hello"</string>;
  <comment>// comment</comment>
}
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					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   {
      uCalc::Transformer t;
      t.Owned(); // Causes t to be released when it goes out of scope
      // 1. Define integer constants for our syntax categories
      auto TAG_KEYWORD = 1;
      auto TAG_STRING = 2;
      auto TAG_COMMENT = 3;

      // 2. Define the transformation rules and tag them
      t.Pattern("{ if | else | for | while }").SetTag(TAG_KEYWORD);
      t.Pattern("{@String}").SetTag(TAG_STRING);
      t.Pattern("// {text}").SetTag(TAG_COMMENT);

      // 3. Set the source code and run the find operation
      string sourceCode = R"(for (i=0; i<10; i++) {
  s = "hello";
  // comment
})";
      t.Text(sourceCode);
      t.Find();

      // 4. Build the highlighted output string
      string highlightedOutput = "";
      auto lastPos = 0;

      for(auto match : t.Matches()) {
         // Append the plain text between the last match and this one
         highlightedOutput = highlightedOutput + sourceCode.substr(lastPos, match.StartPosition() - lastPos);

         // Get the tag and wrap the matched text accordingly
         auto tag = match.Rule().Tag();
         if (tag == TAG_KEYWORD) {
            highlightedOutput = highlightedOutput + "<keyword>" + match.Text() + "</keyword>";
         } else if (tag == TAG_STRING) {
            highlightedOutput = highlightedOutput + "<string>" + match.Text() + "</string>";
         } else if (tag == TAG_COMMENT) {
            highlightedOutput = highlightedOutput + "<comment>" + match.Text() + "</comment>";
         } else {
            highlightedOutput = highlightedOutput + match.Text(); // No tag, append as-is
         }

         // Update the position for the next iteration
         lastPos = match.EndPosition();
      }

      // Append any remaining text after the last match
      highlightedOutput = highlightedOutput + sourceCode.substr(lastPos);

      cout << highlightedOutput << endl;
   }
}
				
			
<keyword>for</keyword> (i=0; i<10; i++) {
  s = <string>"hello"</string>;
  <comment>// comment</comment>
}
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					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      Using t As New uCalc.Transformer()
         '// 1. Define integer constants for our syntax categories
         Dim TAG_KEYWORD = 1
         Dim TAG_STRING = 2
         Dim TAG_COMMENT = 3
         
         '// 2. Define the transformation rules and tag them
         t.Pattern("{ if | else | for | while }").SetTag(TAG_KEYWORD)
         t.Pattern("{@String}").SetTag(TAG_STRING)
         t.Pattern("// {text}").SetTag(TAG_COMMENT)
         
         '// 3. Set the source code and run the find operation
         Dim sourceCode As String = "for (i=0; i<10; i++) {
  s = ""hello"";
  // comment
}"
         t.Text = sourceCode
         t.Find()
         
         '// 4. Build the highlighted output string
         Dim highlightedOutput As String = ""
         Dim lastPos = 0
         
         For Each match In t.Matches
            '// Append the plain text between the last match and this one
            highlightedOutput = highlightedOutput + sourceCode.Substring(lastPos, match.StartPosition - lastPos)
            
            '// Get the tag and wrap the matched text accordingly
            Dim tag = match.Rule.Tag
            If tag = TAG_KEYWORD Then
               highlightedOutput = highlightedOutput + "<keyword>" + match.Text + "</keyword>"
               ElseIf tag = TAG_STRING Then
               highlightedOutput = highlightedOutput + "<string>" + match.Text + "</string>"
               ElseIf tag = TAG_COMMENT Then
               highlightedOutput = highlightedOutput + "<comment>" + match.Text + "</comment>"
            Else
               highlightedOutput = highlightedOutput + match.Text '// No tag, append as-is
            End If
            
            '// Update the position for the next iteration
            lastPos = match.EndPosition
         Next
         
         '// Append any remaining text after the last match
         highlightedOutput = highlightedOutput + sourceCode.Substring(lastPos)
         
         Console.WriteLine(highlightedOutput)
      End Using
   End Sub
End Module
				
			
<keyword>for</keyword> (i=0; i<10; i++) {
  s = <string>"hello"</string>;
  <comment>// comment</comment>
}
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