feat: ast structure and utilities

src/Parse.zig

@@ -0,0 +1,67 @@
+const std = @import("std");
+const assert = std.debug.assert;
+const tok = @import("tokenizer.zig");
+const Token = tok.Token;
+const Tokenizer = tok.Tokenizer;
+const Ast = @import("Ast.zig");
+
+const Parse = @This();
+
+gpa: std.mem.Allocator,
+arena: std.mem.Allocator,
+tokenizer: Tokenizer,
+token: Token,
+scratch: std.ArrayListUnmanaged(*Ast.Node),
+grammar_stack: std.ArrayListUnmanaged(ScanContext),
+block_stack: std.ArrayListUnmanaged(State),
+choice_stack: std.ArrayListUnmanaged(State),
+errors: std.ArrayListUnmanaged(Ast.Error),
+panic_mode: bool,
+flags: u32,
+max_parse_depth: usize,
+max_argument_count: usize,
+knot_offset: usize = 0,
+
+pub const Error = error{
+    ParseError,
+    OutOfMemory,
+};
+
+pub const State = struct {
+    level: usize,
+    scratch_offset: usize,
+    source_offset: usize,
+};
+
+pub const StmtContext = struct {
+    tag: Tag,
+    is_block_created: bool = false,
+    expression_node: ?*Ast.Node = null,
+    level: usize = 0,
+    blocks_top: usize,
+    choices_top: usize,
+    scratch_top: usize,
+
+    pub const Tag = enum {
+        block,
+        conditional,
+    };
+};
+
+pub const ScanContext = struct {
+    grammar: Tokenizer.Grammar,
+    source_offset: usize,
+};
+
+pub fn deinit(p: *Parse) void {
+    p.scratch.deinit(p.gpa);
+    p.grammar_stack.deinit(p.gpa);
+    p.block_stack.deinit(p.gpa);
+    p.choice_stack.deinit(p.gpa);
+    p.errors.deinit(p.gpa);
+    p.* = undefined;
+}
+
+pub fn parseFile(_: *Parse) Error!*Ast.Node {
+    return error.OutOfMemory;
+}