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const std = @import("std");
const jv = @import("../jv.zig");
const tokenize = @import("./tokenize.zig").tokenize;
const parse = @import("./parse.zig").parse;
const Instr = @import("./compile.zig").Instr;
const compile = @import("./compile.zig").compile;
pub const ExecuteError = error{
Unimplemented,
InvalidType,
InternalError,
};
const SaveableStack = @import("./saveable_stack.zig").SaveableStack;
const ValueStack = struct {
const Self = @This();
const Stack = SaveableStack(jv.Value);
stack: Stack,
pub fn init(allocator: std.mem.Allocator) !Self {
return .{
.stack = try Stack.init(allocator),
};
}
pub fn deinit(self: *Self) void {
self.stack.deinit();
}
pub fn push(self: *Self, value: jv.Value) !void {
try self.stack.push(value);
}
pub fn pop(self: *Self) jv.Value {
return self.stack.pop();
}
pub fn popInteger(self: *Self) ExecuteError!i64 {
const value = self.pop();
return switch (value) {
.integer => |i| i,
else => error.InvalidType,
};
}
pub fn popNumber(self: *Self) ExecuteError!f64 {
const value = self.pop();
return switch (value) {
.integer => |i| @floatFromInt(i),
.float => |f| f,
else => error.InvalidType,
};
}
pub fn popString(self: *Self) ExecuteError![]const u8 {
const value = self.pop();
return switch (value) {
.string => |s| s,
else => error.InvalidType,
};
}
pub fn popArray(self: *Self) ExecuteError!jv.Array {
const value = self.pop();
return switch (value) {
.array => |a| a,
else => error.InvalidType,
};
}
pub fn popObject(self: *Self) ExecuteError!jv.Object {
const value = self.pop();
return switch (value) {
.object => |o| o,
else => error.InvalidType,
};
}
pub fn dup(self: *Self) !void {
const top = self.stack.top().*;
try self.push(top);
}
pub fn swap(self: *Self) !void {
std.debug.assert(self.ensureSize(2));
const a = self.pop();
const b = self.pop();
try self.push(a);
try self.push(b);
}
pub fn save(self: *Self) !void {
try self.stack.save();
}
pub fn restore(self: *Self) void {
self.stack.restore();
}
pub fn ensureSize(self: *Self, n: usize) bool {
return self.stack.ensureSize(n);
}
};
pub const Runtime = struct {
const Self = @This();
allocator: std.mem.Allocator,
values: ValueStack,
forks: std.ArrayList(usize),
instrs: []const Instr,
pc: usize,
pub fn init(allocator: std.mem.Allocator) !Self {
return .{
.allocator = allocator,
.values = try ValueStack.init(allocator),
.forks = .{},
.instrs = &[_]Instr{},
.pc = 0,
};
}
pub fn deinit(self: *Self) void {
for (self.instrs) |instr| {
instr.deinit(self.allocator);
}
self.allocator.free(self.instrs);
self.values.deinit();
self.forks.deinit(self.allocator);
}
pub fn compileFromReader(self: *Self, reader: *std.Io.Reader) !void {
std.debug.assert(self.instrs.len == 0);
var compile_allocator = std.heap.ArenaAllocator.init(self.allocator);
defer compile_allocator.deinit();
const tokens = try tokenize(compile_allocator.allocator(), reader);
const ast = try parse(self.allocator, compile_allocator.allocator(), tokens);
const instrs = try compile(self.allocator, compile_allocator.allocator(), ast);
self.instrs = instrs;
// std.debug.print("BEGIN\n", .{});
// for (self.instrs) |instr| {
// std.debug.print("{}\n", .{instr});
// }
// std.debug.print("END\n", .{});
}
pub fn compileFromSlice(self: *Self, query: []const u8) !void {
var reader = std.Io.Reader.fixed(query);
return self.compileFromReader(&reader);
}
pub fn start(self: *Self, input: jv.Value) !void {
try self.values.push(input);
}
pub fn next(self: *Self) !?jv.Value {
std.debug.assert(self.instrs.len > 0);
self.restore_stack();
while (self.pc < self.instrs.len) : (self.pc += 1) {
const cur = self.instrs[self.pc];
// std.debug.print("{}\n", .{cur});
switch (cur) {
.nop => {},
.ret => {
self.pc += 1;
return self.values.pop();
},
.jump => |offset| {
self.pc += offset - 1;
},
.fork => |offset| {
try self.save_stack(self.pc + offset);
},
.subexp_begin => try self.values.dup(),
.subexp_end => try self.values.swap(),
.array_index => {
std.debug.assert(self.values.ensureSize(2));
const array = try self.values.popArray();
const index: usize = @intCast(try self.values.popInteger());
const result = if (index < array.items.len) array.items[index] else .null;
try self.values.push(result);
},
.add => {
std.debug.assert(self.values.ensureSize(3));
_ = self.values.pop();
const lhs = try self.values.popInteger();
const rhs = try self.values.popInteger();
const result = lhs + rhs;
try self.values.push(.{ .integer = result });
},
.sub => {
std.debug.assert(self.values.ensureSize(3));
_ = self.values.pop();
const lhs = try self.values.popInteger();
const rhs = try self.values.popInteger();
const result = lhs - rhs;
try self.values.push(.{ .integer = result });
},
.mul => {
std.debug.assert(self.values.ensureSize(3));
_ = self.values.pop();
const lhs = try self.values.popInteger();
const rhs = try self.values.popInteger();
const result = lhs * rhs;
try self.values.push(.{ .integer = result });
},
.div => {
std.debug.assert(self.values.ensureSize(3));
_ = self.values.pop();
const lhs = try self.values.popInteger();
const rhs = try self.values.popInteger();
const result = @divTrunc(lhs, rhs);
try self.values.push(.{ .integer = result });
},
.mod => {
std.debug.assert(self.values.ensureSize(3));
_ = self.values.pop();
const lhs = try self.values.popInteger();
const rhs = try self.values.popInteger();
const result = @mod(lhs, rhs);
try self.values.push(.{ .integer = result });
},
.eq => {
std.debug.assert(self.values.ensureSize(3));
_ = self.values.pop();
const lhs = self.values.pop();
const rhs = self.values.pop();
const result = try compareValues(lhs, rhs, .eq);
try self.values.push(.{ .bool = result });
},
.ne => {
std.debug.assert(self.values.ensureSize(3));
_ = self.values.pop();
const lhs = self.values.pop();
const rhs = self.values.pop();
const result = try compareValues(lhs, rhs, .ne);
try self.values.push(.{ .bool = result });
},
.lt => {
std.debug.assert(self.values.ensureSize(3));
_ = self.values.pop();
const lhs = self.values.pop();
const rhs = self.values.pop();
const result = try compareValues(lhs, rhs, .lt);
try self.values.push(.{ .bool = result });
},
.gt => {
std.debug.assert(self.values.ensureSize(3));
_ = self.values.pop();
const lhs = self.values.pop();
const rhs = self.values.pop();
const result = try compareValues(lhs, rhs, .gt);
try self.values.push(.{ .bool = result });
},
.le => {
std.debug.assert(self.values.ensureSize(3));
_ = self.values.pop();
const lhs = self.values.pop();
const rhs = self.values.pop();
const result = try compareValues(lhs, rhs, .le);
try self.values.push(.{ .bool = result });
},
.ge => {
std.debug.assert(self.values.ensureSize(3));
_ = self.values.pop();
const lhs = self.values.pop();
const rhs = self.values.pop();
const result = try compareValues(lhs, rhs, .ge);
try self.values.push(.{ .bool = result });
},
.object_key => |key| {
std.debug.assert(self.values.ensureSize(1));
const obj = try self.values.popObject();
const result = obj.get(key) orelse .null;
try self.values.push(result);
},
.literal => |value| {
std.debug.assert(self.values.ensureSize(1));
_ = self.values.pop();
try self.values.push(value.*);
},
}
}
return null;
}
fn save_stack(self: *Self, target_pc: usize) !void {
try self.forks.append(self.allocator, target_pc);
try self.values.save();
}
fn restore_stack(self: *Self) void {
if (self.forks.pop()) |target_pc| {
self.pc = target_pc;
self.values.restore();
}
}
};
const CompareOp = enum { eq, ne, lt, gt, le, ge };
fn compareValues(lhs: jv.Value, rhs: jv.Value, op: CompareOp) ExecuteError!bool {
const lhs_tag = std.meta.activeTag(lhs);
const rhs_tag = std.meta.activeTag(rhs);
if (lhs_tag != rhs_tag) {
const lhs_is_number = lhs_tag == .integer or lhs_tag == .float;
const rhs_is_number = rhs_tag == .integer or rhs_tag == .float;
if (lhs_is_number and rhs_is_number) {
return compareNumbers(lhs, rhs, op);
}
return error.InvalidType;
}
return switch (lhs) {
.null => switch (op) {
.eq => true,
.ne => false,
.lt, .gt, .le, .ge => error.Unimplemented,
},
.bool => |lhs_bool| {
const rhs_bool = rhs.bool;
return switch (op) {
.eq => lhs_bool == rhs_bool,
.ne => lhs_bool != rhs_bool,
.lt, .gt, .le, .ge => error.Unimplemented,
};
},
.integer, .float => compareNumbers(lhs, rhs, op),
.string => |lhs_str| {
const rhs_str = rhs.string;
const order = std.mem.order(u8, lhs_str, rhs_str);
return switch (op) {
.eq => order == .eq,
.ne => order != .eq,
.lt => order == .lt,
.gt => order == .gt,
.le => order == .lt or order == .eq,
.ge => order == .gt or order == .eq,
};
},
.array => switch (op) {
.eq, .ne => error.Unimplemented,
.lt, .gt, .le, .ge => error.Unimplemented,
},
.object => switch (op) {
.eq, .ne => error.Unimplemented,
.lt, .gt, .le, .ge => error.Unimplemented,
},
.number_string => error.Unimplemented,
};
}
fn compareNumbers(lhs: jv.Value, rhs: jv.Value, op: CompareOp) bool {
const lhs_f: f64 = switch (lhs) {
.integer => |i| @floatFromInt(i),
.float => |f| f,
else => unreachable,
};
const rhs_f: f64 = switch (rhs) {
.integer => |i| @floatFromInt(i),
.float => |f| f,
else => unreachable,
};
return switch (op) {
.eq => lhs_f == rhs_f,
.ne => lhs_f != rhs_f,
.lt => lhs_f < rhs_f,
.gt => lhs_f > rhs_f,
.le => lhs_f <= rhs_f,
.ge => lhs_f >= rhs_f,
};
}
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