Add fin keyword

docs/syntax.md

@@ -37,6 +37,8 @@ As a convenience, if you don't pass in a jump to the CLI the first bough in the
 # topi run file.topi // START will run in the above example
 ```
 
+Be careful though, if you include other files the "first" bough will be the first in the other file.
+
 ### Nesting
 
 Boughs can be nested and jumped to with `.` like so:
@@ -201,9 +203,18 @@ Visit paths can be found within scopes and don't need the full path written out.
 }
 ```
 
-### Flow and Jump Back Ups
+### Flow, Fin, and Jump Back Ups
+
+If the flow of the story hits a closing backet or `fin`, it will end. 
+`fin` can be useful to break out of a bough early.
+
+```topi
+=== START {
+    if (true) fin
+    :: "Will not get here"
+}
+```
 
-If the flow of the story hits a closing backet it will end. 
 But sometimes we want to temporarily duck into a bough and then continue on.
 We can do that by adding a caret `^` to a jump name `=> [NAME]^` (meaning jump then come back up).
 
@@ -441,7 +452,7 @@ const fib = |n| {
 }
 ```
 
-## Return Void
+#### Return Void
 
 If you want to return out of a function early you have to specify `return void` and not just `return` like most langauges.
 

src/ast.zig

@@ -176,6 +176,7 @@ pub const Statement = struct {
         },
         return_expression: Expression,
         return_void: void,
+        fin: void,
         class: struct {
             name: []const u8,
             field_names: [][]const u8,

src/compiler.zig

@@ -699,6 +699,9 @@ pub const Compiler = struct {
             .return_void => {
                 try self.writeOp(.return_void, token);
             },
+            .fin => {
+                try self.writeOp(.fin, token);
+            },
             else => {},
         }
     }

src/parser.zig

@@ -117,6 +117,7 @@ pub const Parser = struct {
             .tilde => try self.choiceStatement(),
             .fork => try self.forkStatement(),
             .@"for" => try self.forStatement(),
+            .fin => .{ .token = self.current_token, .type = .fin },
             .@"if" => try self.ifStatement(),
             .@"switch" => try self.switchStatement(),
             .@"while" => try self.whileStatement(),

src/token.zig

@@ -84,8 +84,9 @@ pub const TokenType = enum {
     @"while",
 
     bough,
-    fork,
     divert,
+    fork,
+    fin,
 
     comment,
     eof,
@@ -105,6 +106,7 @@ pub const Keywords = std.StaticStringMap(TokenType).initComptime(.{
     .{ "false", .false },
     .{ "for", .@"for" },
     .{ "fork", .fork },
+    .{ "fin", .fin },
     .{ "if", .@"if" },
     .{ "include", .include },
     .{ "List", .list },
@@ -194,8 +196,9 @@ pub fn toString(token_type: TokenType) []const u8 {
         .@"while" => "while",
 
         .bough => "bough",
-        .fork => "fork",
         .divert => "=>",
+        .fork => "fork",
+        .fin => "fin",
 
         .comment => "[comment]",
         .eof => "[eof]",

src/vm.test.zig

@@ -1357,6 +1357,18 @@ test "Jump Code" {
             \\ }
             ,
         },
+        .{
+            .input =
+            \\ === START {
+            \\    => INNER^
+            \\    :: "Fin executed correctly"
+            \\    === INNER {
+            \\        if (INNER == 1) fin
+            \\        :: "Fin did not work!"
+            \\    }
+            \\ }
+            ,
+        },
     };
 
     inline for (test_cases) |case| {