Parser support for functions and function calls. No returns yet.

Starship/Rockstar.Engine/Expressions/Expression.cs

@@ -8,4 +8,8 @@ public virtual void Print(StringBuilder sb, string prefix)
 		=> sb.Append(prefix).AppendLine(this.GetType().Name.ToLowerInvariant());
 
 	protected string Location => source.Location;
+
+	public List<Expression> Concat(List<Expression> list)
+		=> new List<Expression> { this }.Concat(list).ToList();
+
 }

Starship/Rockstar.Engine/Expressions/Variable.cs

@@ -16,4 +16,7 @@ protected string NormalizedName
 		=> String.Join("_", whitespace.Split(Name));
 
 	public abstract string Key { get; }
+
+	public List<Variable> Concat(List<Variable> list)
+		=> new List<Variable> { this }.Concat(list).ToList();
 }

Starship/Rockstar.Engine/Statements/Statement.cs

@@ -1,4 +1,5 @@
 using System.Text;
+using Rockstar.Engine.Expressions;
 
 namespace Rockstar.Engine.Statements;
 
@@ -8,3 +9,23 @@ public abstract class Statement(Source source) {
 	protected string Location => source.Location;
 }
 
+public class Function(Variable name, IEnumerable<Variable> args, Block body, Source source)
+	: Statement(source) {
+	public override void Print(StringBuilder sb, string prefix = "") {
+		sb.Append(prefix).Append($"function: {name.Name}(");
+		sb.Append(String.Join(", ", args.Select(a => a.Name)));
+		sb.AppendLine(")");
+		body.Print(sb, prefix + "|" + INDENT);
+	}
+}
+
+public class FunctionCall(Variable name, List<Expression> args, Source source)
+	: Statement(source) {
+	public override void Print(StringBuilder sb, string prefix = "") {
+		sb.Append(prefix).AppendLine($"function call: {name.Name}");
+		foreach (var arg in args) {
+			arg.Print(sb, prefix + INDENT);
+		}
+	}
+}
+

Starship/Rockstar.Engine/rockstar.peg

@@ -35,9 +35,37 @@ statement <Statement>
 	= loop
 	/ alternate
 	/ output_stmt
+	/ function_call
+	/ function
 	/ assign_stmt
 	/ increment
 	/ decrement
+
+
+takes = ('takes' / 'wants')
+
+function <Function>
+	= name:variable _ takes _ args:variable_list EOS body:statements
+		{ new Function(name, args, body, state.Source()) }
+
+function_call <FunctionCall>
+	= name:variable _ 'taking' _ args:expression_list
+		{ new FunctionCall(name, args, state.Source()) }
+
+expression_list <List<Expression>>
+	= head:expression _XLS_ tail:expression_list
+		{ head.Concat(tail) }
+	/ expr:expression { new List<Expression> { expr } }
+
+_XLS_
+	= (_? ', and' _ / _? ('&' / ',' / "'n'") _?)
+
+_VLS_ = _XLS_ / _ 'and' _
+
+variable_list <List<Variable>>
+	= head:variable _VLS_ tail:variable_list
+		{ head.Concat(tail) }
+  / arg:variable { new List<Variable> { arg } }
 
 noise 	= (_ / [;,])
 

Starship/Rockstar.Test/ConditionalTests.cs

@@ -2,71 +2,6 @@
 
 namespace Rockstar.Test;
 
-public class LoopTests(ITestOutputHelper output) : ParserTestBase(output) {
-	[Theory]
-	[InlineData("while true say loop")]
-	[InlineData("""
-	            while true
-	            say loop1
-	            say loop2
-	            say loop3
-
-	            say done
-	            """)]
-	public void ParserParsesLoop(string source) => Parse(source);
-
-	[Theory]
-	[InlineData("""
-				X is 10
-				While X is greater than nothing
-				While Y is less than 3
-				Build Y up
-				Say Y
-
-				Knock X down
-
-				""")]
-	public void ParserParsesNestedLoop(string source) {
-		var parsed = Parse(source);
-		parsed.Statements.Count.ShouldBe(2);
-	}
-
-	[Fact]
-	public void WhileLoopWorks() {
-		var source = """
-		             let i be 0
-		             while i is less than 5
-		             say i
-		             build i up
-
-		             say "finished"
-		             """;
-		var parsed = Parse(source);
-		var e = new TestEnvironment();
-		var i = new Interpreter(e);
-		var result = i.Exec(parsed);
-		e.Output.ReplaceLineEndings().ShouldBe("0\n1\n2\n3\n4\nfinished\n".ReplaceLineEndings());
-	}
-
-	[Fact]
-	public void UntilLoopWorks() {
-		var source = """
-		             let i be 0
-		             until i is as great as 5
-		             say i
-		             build i up
-
-		             say "finished"
-		             """;
-		var parsed = Parse(source);
-		var e = new TestEnvironment();
-		var i = new Interpreter(e);
-		var result = i.Exec(parsed);
-		e.Output.ReplaceLineEndings().ShouldBe("0\n1\n2\n3\n4\nfinished\n".ReplaceLineEndings());
-	}
-
-}
-
 public class ConditionalTests(ITestOutputHelper output) {
 	[Theory]
 	[InlineData("if true say 1")]

Starship/Rockstar.Test/FunLyricTests.cs

@@ -0,0 +1,10 @@
+namespace Rockstar.Test;
+
+public class FunLyricTests(ITestOutputHelper output) : ParserTestBase(output) {
+
+	[Theory]
+	[InlineData("It's more than a feeling (More than a feeling)")]
+	[InlineData("If it's more than a feeling (More than a feeling) say yeah")]
+	public void ParserParsesLyric(string source)
+		=> Parse(source);
+}

Starship/Rockstar.Test/FunctionTests.cs

@@ -0,0 +1,23 @@
+namespace Rockstar.Test;
+
+public class FunctionTests(ITestOutputHelper output) : ParserTestBase(output) {
+	[Theory]
+	[InlineData("""
+	            Echo takes X
+	            say X
+	            (end function)
+	            """)]
+	[InlineData("sum taking 2, 3")]
+	[InlineData("""
+	            Echo takes X
+	            say X
+	            (end function)
+	            Echo taking true
+	            Echo taking "hello world"
+	            put 5 into Temp
+	            Echo taking Temp
+	            """)]
+	public void ParserParsesFunctions(string source) {
+		var result = Parse(source);
+	}
+}

Starship/Rockstar.Test/LoopTests.cs

@@ -0,0 +1,66 @@
+namespace Rockstar.Test;
+
+public class LoopTests(ITestOutputHelper output) : ParserTestBase(output) {
+	[Theory]
+	[InlineData("while true say loop")]
+	[InlineData("""
+	            while true
+	            say loop1
+	            say loop2
+	            say loop3
+
+	            say done
+	            """)]
+	public void ParserParsesLoop(string source) => Parse(source);
+
+	[Theory]
+	[InlineData("""
+	            X is 10
+	            While X is greater than nothing
+	            While Y is less than 3
+	            Build Y up
+	            Say Y
+
+	            Knock X down
+
+	            """)]
+	public void ParserParsesNestedLoop(string source) {
+		var parsed = Parse(source);
+		parsed.Statements.Count.ShouldBe(2);
+	}
+
+	[Fact]
+	public void WhileLoopWorks() {
+		var source = """
+		             let i be 0
+		             while i is less than 5
+		             say i
+		             build i up
+
+		             say "finished"
+		             """;
+		var parsed = Parse(source);
+		var e = new TestEnvironment();
+		var i = new Interpreter(e);
+		var result = i.Exec(parsed);
+		e.Output.ReplaceLineEndings().ShouldBe("0\n1\n2\n3\n4\nfinished\n".ReplaceLineEndings());
+	}
+
+	[Fact]
+	public void UntilLoopWorks() {
+		var source = """
+		             let i be 0
+		             until i is as great as 5
+		             say i
+		             build i up
+
+		             say "finished"
+		             """;
+		var parsed = Parse(source);
+		var e = new TestEnvironment();
+		var i = new Interpreter(e);
+		var result = i.Exec(parsed);
+		e.Output.ReplaceLineEndings().ShouldBe("0\n1\n2\n3\n4\nfinished\n".ReplaceLineEndings());
+	}
+
+}

Starship/Rockstar.Test/ParserTestBase.cs

@@ -9,13 +9,4 @@ protected Block Parse(string source) {
 		output.WriteLine(result.ToString());
 		return result;
 	}
-}
-
-public class FunLyricTests(ITestOutputHelper output) : ParserTestBase(output) {
-
-	[Theory]
-	[InlineData("It's more than a feeling (More than a feeling)")]
-	[InlineData("If it's more than a feeling (More than a feeling) say yeah")]
-	public void ParserParsesLyric(string source)
-		=> Parse(source);
 }

Starship/Rockstar.Test/Rockstar.Test.v3.ncrunchproject

@@ -5,9 +5,6 @@
       <FixtureTestSelector>
         <FixtureName>Rockstar.Test.FixturePreTests</FixtureName>
       </FixtureTestSelector>
-      <FixtureTestSelector>
-        <FixtureName>Rockstar.Test.FixtureTests</FixtureName>
-      </FixtureTestSelector>
     </IgnoredTests>
   </Settings>
 </ProjectConfiguration>