1 files changed, 59 insertions, 0 deletions
diff --git a/src/parser.zig b/src/parser.zig
new file mode 100644
index 0000000..422c9cb
--- /dev/null
+++ b/src/parser.zig
@@ -0,0 +1,59 @@
+const std = @import("std");
+const tok = @import("tokenize.zig");
+const Iterator = tok.Iterator;
+const Token = tok.Token;
+
+const ParsingError = error{ InvalidExpression, ExpectedExit, ExpectedSemicolon };
+
+pub const NodeExpr = struct {
+    intLit: Token,
+};
+
+pub const NodeExit = struct {
+    expr: NodeExpr,
+};
+
+pub const Parser = struct {
+    tokens: Iterator(Token),
+
+    pub fn init(tokens: []Token) Parser {
+        return .{
+            .tokens = Iterator(Token).init(tokens),
+        };
+    }
+
+    fn parseExpr(self: *Parser) !NodeExpr {
+        if (tok.checkType(self.tokens.peek().?, tok.TokenType.intLit))
+            return NodeExpr{ .intLit = self.tokens.consume().? };
+        return ParsingError.InvalidExpression;
+    }
+
+    pub fn parse(self: *Parser) !NodeExit {
+        var root: NodeExit = undefined;
+        while (self.tokens.peek()) |token| {
+            switch (token) {
+                .exit => {
+                    self.tokens.skip();
+                    root.expr = try self.parseExpr();
+                    if (!tok.checkType(self.tokens.peek().?, tok.TokenType.semiCol))
+                        return ParsingError.ExpectedSemicolon;
+                    self.tokens.skip();
+                },
+                else => return ParsingError.ExpectedExit,
+            }
+        }
+        return root;
+    }
+};
+
+test "Parser" {
+    const expect = std.testing.expect;
+    const src = "exit 120;";
+    var tokenizer = tok.Tokenizer.init(std.testing.allocator, src);
+    defer tokenizer.deinit();
+    const toks = try tokenizer.tokenize();
+    var parser = Parser.init(toks);
+    const parseTree = try parser.parse();
+    const exp = NodeExit{ .expr = NodeExpr{ .intLit = Token{ .intLit = 120 } } };
+    try expect(std.meta.eql(parseTree, exp));
+}