TextApi

C# REPL

CSharpScriptHost is a Roslyn-backed scripting engine that lets you run arbitrary C# code with full access to the document and cursor objects. Variables persist across submissions, so you can build up state interactively.

Navigation: Overview

Script DSL

Examples

Quick Start

Basic Usage

using TextAPI.Repl;
using TextAPI.Core.Cursor;

var doc = new TextDocument();
doc.Load("Hello\nWorld");

var mc = new MultiCursor(doc);
var host = new CSharpScriptHost(doc, mc);

// First submission: define a variable
var r1 = await host.ExecuteAsync("var n = doc.LineCount;");
Console.WriteLine($"Executed: {r1.Success}");

// Second submission: use the variable (n is still in scope)
var r2 = await host.ExecuteAsync("Print(n + 1);");
Console.WriteLine(r2.Output);  // "3" (assuming 2 lines)

ExecutionResult

Property	Type	Description
Success	bool	Whether the code compiled and executed.
Output	string	Captured console output.
Error	string?	Compilation or runtime error message.
ReturnValue	object?	Value returned by the expression (if any).

Available Objects in Scope

• doc: The TextDocument instance
• mc: The MultiCursor instance
• Print(object value): Equivalent to Console.WriteLine()
• All imported namespaces (TextAPI, System, etc.)

Persistence

Variables and functions defined in one submission remain in scope for subsequent submissions:

await host.ExecuteAsync("var x = 42;");
await host.ExecuteAsync("var y = x + 8;");
await host.ExecuteAsync("Print(y);");  // 50

Common Workflows

Query the Document

await host.ExecuteAsync(@"
	var lines = doc.LineCount;
	var len = doc.Length;
	Print($""{lines} lines, {len} chars"");
");

Modify with Cursors

await host.ExecuteAsync(@"
	mc.AddColumnSelection(0, 5, 0);
	mc.InsertText(""// "");
");

Use Operations

await host.ExecuteAsync(@"
	using TextAPI.Operations;
	var result = new DocumentPipeline(doc)
		.Add(new ReplaceAllOperation { Find = ""TODO"", Replace = ""DONE"" })
		.Execute();
	Print(result.Success ? ""Done"" : ""Failed"");
");

Error Handling

var result = await host.ExecuteAsync("invalid c# code");
if (!result.Success)
	Console.WriteLine($"Error: {result.Error}");