step5 sdlang used for config files and doc headers

1 files changed, 61 insertions, 0 deletions

diff --git a/src/sdlang/symbol.d b/src/sdlang/symbol.d
new file mode 100644
index 0000000..14a74a7
--- /dev/null
+++ b/src/sdlang/symbol.d
@@ -0,0 +1,61 @@
+// SDLang-D
+// Written in the D programming language.
+
+module sdlang.symbol;
+
+import std.algorithm;
+
+static immutable validSymbolNames = [
+	"Error",
+	"EOF",
+	"EOL",
+
+	":",
+	"=",
+	"{",
+	"}",
+
+	"Ident",
+	"Value",
+];
+
+/// Use this to create a Symbol. Ex: symbol!"Value" or symbol!"="
+/// Invalid names (such as symbol!"FooBar") are rejected at compile-time.
+template symbol(string name)
+{
+	static assert(validSymbolNames.find(name), "Invalid Symbol: '"~name~"'");
+	immutable symbol = _symbol(name);
+}
+
+private Symbol _symbol(string name)
+{
+	return Symbol(name);
+}
+
+/// Symbol is essentially the "type" of a Token.
+/// Token is like an instance of a Symbol.
+///
+/// This only represents terminals. Nonterminal tokens aren't
+/// constructed since the AST is built directly during parsing.
+///
+/// You can't create a Symbol directly. Instead, use the 'symbol'
+/// template.
+struct Symbol
+{
+	private string _name;
+	@property string name()
+	{
+		return _name;
+	}
+	
+	@disable this();
+	private this(string name)
+	{
+		this._name = name;
+	}
+
+	string toString()
+	{
+		return _name;
+	}
+}