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riddle/
language.rs

1use crate::{
2    RiddleError,
3    env::{BoolExpr, CommonEnv, Env, Slot, Var, get_var_by_path, to_cnf},
4    scope::{Scope, Type, get_type_by_path, is_assignable_from},
5};
6use std::{
7    collections::{HashMap, VecDeque},
8    fmt,
9    rc::Rc,
10};
11
12pub struct ProblemDef {
13    pub functions: Vec<FunctionDef>,
14    pub predicates: Vec<PredicateDef>,
15    pub classes: Vec<ClassDef>,
16    pub statements: Vec<Statement>,
17}
18
19pub type FieldDef = (Vec<String>, Vec<(String, Option<Expr>)>); // (type, [(name, optional initializer)])
20
21pub struct ClassDef {
22    pub name: String,
23    pub parents: Vec<Vec<String>>,
24    pub fields: Vec<FieldDef>,
25    pub constructors: Vec<ConstructorDef>,
26    pub functions: Vec<FunctionDef>,
27    pub predicates: Vec<PredicateDef>,
28    pub classes: Vec<ClassDef>,
29}
30
31pub struct ConstructorDef {
32    pub args: Vec<(Vec<String>, String)>,
33    pub init: Vec<(Vec<String>, Vec<Expr>)>,
34    pub statements: Vec<Statement>,
35}
36
37pub struct FunctionDef {
38    pub return_type: Option<Vec<String>>,
39    pub name: String,
40    pub args: Vec<(Vec<String>, String)>,
41    pub statements: Vec<Statement>,
42}
43
44pub struct PredicateDef {
45    pub name: String,
46    pub args: Vec<(Vec<String>, String)>,
47    pub parents: Vec<Vec<String>>,
48    pub statements: Vec<Statement>,
49}
50
51#[derive(Debug, PartialEq, Clone)]
52pub enum Statement {
53    Expr(Expr),
54    LocalField { field_type: Vec<String>, fields: Vec<(String, Option<Expr>)> },
55    Assign { name: Vec<String>, value: Expr },
56    ForAll { var_type: Vec<String>, var_name: String, statements: Vec<Statement> },
57    Disjunction { disjuncts: Vec<(Vec<Statement>, Expr)> },
58    Formula { is_fact: bool, name: String, tau: Vec<String>, predicate_name: String, args: Vec<(String, Expr)> },
59    Return { value: Expr },
60}
61
62impl fmt::Display for Statement {
63    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
64        match self {
65            Statement::Expr(e) => write!(f, "{};", e),
66            Statement::LocalField { field_type, fields } => write!(f, "{} {};", field_type.join("."), fields.iter().map(|(n, v)| format!("{}{}", n, v.as_ref().map(|v| format!(" = {}", v)).unwrap_or_default())).collect::<Vec<_>>().join(", ")),
67            Statement::Assign { name, value } => write!(f, "{} = {};", name.join("."), value),
68            Statement::ForAll { var_type, var_name, statements } => write!(f, "for {} {} {{\n{}\n}}", var_type.join("."), var_name, statements.iter().map(|s| format!("    {}", s)).collect::<Vec<_>>().join("\n")),
69            Statement::Disjunction { disjuncts } => write!(f, "{{\n{}\n}}", disjuncts.iter().map(|(s, e)| format!("    {{\n{}\n    }}: {}", s.iter().map(|s| format!("        {}", s)).collect::<Vec<_>>().join("\n"), e)).collect::<Vec<_>>().join(" or ")),
70            Statement::Formula { is_fact, name, tau, predicate_name, args } => write!(f, "{} {} = new {}{}({});", if *is_fact { "fact" } else { "formula" }, name, if tau.is_empty() { String::new() } else { tau.join(".") + "." }, predicate_name, args.iter().map(|(n, e)| format!("{}: {}", n, e)).collect::<Vec<_>>().join(", ")),
71            Statement::Return { value } => write!(f, "return {};", value),
72        }
73    }
74}
75
76#[derive(Debug, PartialEq, Clone)]
77pub enum Expr {
78    Bool(bool),
79    Int(i64),
80    Real(i64, i64),
81    String(String),
82    QualifiedId { ids: Vec<String> },
83    Sum { terms: Vec<Expr> },
84    Opposite { term: Box<Expr> },
85    Not { term: Box<Expr> },
86    Mul { factors: Vec<Expr> },
87    Div { left: Box<Expr>, right: Box<Expr> },
88    Function { name: Vec<String>, args: Vec<Expr> },
89    Eq { left: Box<Expr>, right: Box<Expr> },
90    Neq { left: Box<Expr>, right: Box<Expr> },
91    Lt { left: Box<Expr>, right: Box<Expr> },
92    Leq { left: Box<Expr>, right: Box<Expr> },
93    Gt { left: Box<Expr>, right: Box<Expr> },
94    Geq { left: Box<Expr>, right: Box<Expr> },
95    Or { terms: Vec<Expr> },
96    And { terms: Vec<Expr> },
97    NewObject { class_name: Vec<String>, args: Vec<Expr> },
98}
99
100impl fmt::Display for Expr {
101    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
102        match self {
103            Expr::Bool(b) => write!(f, "{}", b),
104            Expr::Int(i) => write!(f, "{}", i),
105            Expr::Real(n, d) => write!(f, "{}/{}", n, d),
106            Expr::String(s) => write!(f, "\"{}\"", s),
107            Expr::QualifiedId { ids } => write!(f, "{}", ids.join(".")),
108            Expr::Sum { terms } => write!(f, "({})", terms.iter().map(|t| format!("{}", t)).collect::<Vec<_>>().join(" + ")),
109            Expr::Opposite { term } => write!(f, "-({})", term),
110            Expr::Not { term } => write!(f, "!({})", term),
111            Expr::Mul { factors } => write!(f, "({})", factors.iter().map(|t| format!("{}", t)).collect::<Vec<_>>().join(" * ")),
112            Expr::Div { left, right } => write!(f, "({} / {})", left, right),
113            Expr::Function { name, args } => write!(f, "{}({})", name.join("."), args.iter().map(|a| format!("{}", a)).collect::<Vec<_>>().join(", ")),
114            Expr::Eq { left, right } => write!(f, "({} == {})", left, right),
115            Expr::Neq { left, right } => write!(f, "({} != {})", left, right),
116            Expr::Lt { left, right } => write!(f, "({} < {})", left, right),
117            Expr::Leq { left, right } => write!(f, "({} <= {})", left, right),
118            Expr::Gt { left, right } => write!(f, "({} > {})", left, right),
119            Expr::Geq { left, right } => write!(f, "({} >= {})", left, right),
120            Expr::Or { terms } => write!(f, "({})", terms.iter().map(|t| format!("{}", t)).collect::<Vec<_>>().join(" || ")),
121            Expr::And { terms } => write!(f, "({})", terms.iter().map(|t| format!("{}", t)).collect::<Vec<_>>().join(" && ")),
122            Expr::NewObject { class_name, args } => write!(f, "new {}({})", class_name.join("."), args.iter().map(|a| format!("{}", a)).collect::<Vec<_>>().join(", ")),
123        }
124    }
125}
126
127pub struct Disjunction {
128    pub scp: Rc<dyn Scope>,
129    pub env: Rc<dyn Env>,
130    pub disjuncts: Vec<(Vec<Statement>, Expr)>,
131}
132
133pub fn execute(scp: &Rc<dyn Scope>, env: Rc<dyn Env>, stmt: &Statement) -> Result<(), RiddleError> {
134    match stmt {
135        Statement::Expr(expr) => {
136            let expr = evaluate(scp.as_ref(), env, expr)?;
137            if let Slot::Primitive(var) = expr.clone()
138                && let Ok(bool_expr) = var.as_any().downcast::<BoolExpr>()
139            {
140                scp.core().assert(to_cnf(bool_expr));
141                Ok(())
142            } else {
143                Err(RiddleError::RuntimeError(format!("Expected boolean expression, got {}", expr)))
144            }
145        }
146        Statement::LocalField { field_type, fields } => {
147            let fld_tp = get_type_by_path(scp.as_ref(), field_type)?;
148            for (name, default) in fields {
149                if let Some(expr) = default {
150                    let value = evaluate(scp.as_ref(), env.clone(), expr)?;
151                    match &value {
152                        Slot::Primitive(var) => {
153                            if !is_assignable_from(&fld_tp, &var.var_type()) {
154                                return Err(RiddleError::TypeError(format!("Default value for field '{}' is not assignable to field type '{}'", name, field_type.join("."))));
155                            }
156                        }
157                        Slot::ObjectRef(obj_id) => {
158                            let obj = scp.core().get_object(*obj_id).ok_or_else(|| RiddleError::NotFound(format!("Object {} not found", *obj_id)))?;
159                            let obj_type: Rc<dyn Type> = obj.class();
160                            if !is_assignable_from(&fld_tp, &obj_type) {
161                                return Err(RiddleError::TypeError(format!("Default value for field '{}' is not assignable to field type '{}'", name, field_type.join("."))));
162                            }
163                        }
164                        Slot::AtomRef(atom_id) => {
165                            let atom = scp.core().get_atom(*atom_id).ok_or_else(|| RiddleError::NotFound(format!("Atom {} not found", *atom_id)))?;
166                            let atom_type: Rc<dyn Type> = atom.predicate();
167                            if !is_assignable_from(&fld_tp, &atom_type) {
168                                return Err(RiddleError::TypeError(format!("Default value for field '{}' is not assignable to field type '{}'", name, field_type.join("."))));
169                            }
170                        }
171                    }
172                    env.set(name.clone(), value);
173                } else if let Some(class) = fld_tp.clone().as_class() {
174                    let instances = class.instances();
175                    if instances.is_empty() {
176                        return Err(RiddleError::RuntimeError(format!("No instances found for field '{}' of type '{}'", name, class.full_name())));
177                    } else if instances.len() == 1 {
178                        env.set(name.clone(), Slot::ObjectRef(instances[0]));
179                    } else {
180                        env.set(name.clone(), scp.core().new_var(class, instances.as_slice())?);
181                    }
182                } else {
183                    env.set(name.clone(), fld_tp.clone().new_instance());
184                }
185            }
186            Ok(())
187        }
188        Statement::Assign { name, value } => {
189            let value = evaluate(scp.as_ref(), env.clone(), value)?;
190            if name.len() == 1 {
191                env.set(name[0].clone(), value);
192                Ok(())
193            } else {
194                let (last, rest) = name.split_last().ok_or_else(|| RiddleError::RuntimeError("Empty assignment path".into()))?;
195                let var = get_var_by_path(scp.core().as_ref(), env.as_ref(), rest)?;
196                match &var {
197                    Slot::Primitive(_) => Err(RiddleError::NotAnEnvironment(format!("Variable '{}' in assignment path is a primitive variable, cannot assign to '{}'", rest.join("."), last))),
198                    Slot::ObjectRef(obj_id) => {
199                        let obj = scp.core().get_object(*obj_id).ok_or_else(|| RiddleError::NotFound(format!("Object {} not found", *obj_id)))?;
200                        obj.as_env().ok_or_else(|| RiddleError::NotAnEnvironment(format!("Object {} does not have an environment", *obj_id)))?.set(last.to_string(), value);
201                        Ok(())
202                    }
203                    Slot::AtomRef(atom_id) => {
204                        let atom = scp.core().get_atom(*atom_id).ok_or_else(|| RiddleError::NotFound(format!("Atom {} not found", *atom_id)))?;
205                        atom.as_env().ok_or_else(|| RiddleError::NotAnEnvironment(format!("Atom {} does not have an environment", *atom_id)))?.set(last.to_string(), value);
206                        Ok(())
207                    }
208                }
209            }
210        }
211        Statement::ForAll { var_type, var_name, statements } => {
212            let class = get_type_by_path(scp.as_ref(), var_type)?.as_class().ok_or_else(|| RiddleError::NotAClass(var_type.join(".")))?;
213            for instance in class.instances() {
214                let loop_env = Rc::new(CommonEnv::new(Some(env.clone())));
215                loop_env.set(var_name.clone(), Slot::ObjectRef(instance));
216                for stmt in statements {
217                    execute(scp, loop_env.clone(), stmt)?;
218                }
219            }
220            Ok(())
221        }
222        Statement::Disjunction { disjuncts } => {
223            let disjunction = Disjunction { scp: scp.clone(), env: env.clone(), disjuncts: disjuncts.clone() };
224            scp.core().new_disjunction(disjunction);
225            Ok(())
226        }
227        Statement::Formula { is_fact, name, tau, predicate_name, args } => {
228            let tau = if tau.is_empty() { None } else { Some(get_var_by_path(scp.core().as_ref(), env.as_ref(), tau)?) };
229            let predicate = if let Some(tau) = tau.as_ref() {
230                let tau = match tau {
231                    Slot::Primitive(var) => Err(RiddleError::NotAClass(format!("Tau variable is a primitive variable of type '{}', expected a class", var.var_type().full_name()))),
232                    Slot::ObjectRef(obj_id) => scp.core().get_object(*obj_id).ok_or_else(|| RiddleError::NotFound(format!("Object {} not found", *obj_id))),
233                    Slot::AtomRef(atom_id) => Err(RiddleError::NotAClass(format!("Tau variable is an atom {}, expected a class", *atom_id))),
234                }?;
235                tau.var_type().as_class().ok_or_else(|| RiddleError::NotAClass(format!("Type '{}' in tau path", tau.var_type().full_name())))?.get_predicate(predicate_name).ok_or_else(|| RiddleError::NotFound(format!("Predicate '{}' in class '{}'", predicate_name, tau.var_type().full_name())))?
236            } else {
237                scp.get_predicate(predicate_name).ok_or_else(|| RiddleError::NotFound(format!("Predicate '{}'", predicate_name)))?
238            };
239            let mut args: HashMap<String, Slot> = args
240                .iter()
241                .map(|(n, e)| {
242                    let val = evaluate(scp.as_ref(), env.clone(), e)?;
243                    Ok((n.clone(), val))
244                })
245                .collect::<Result<_, _>>()?;
246            if let Some(tau) = tau {
247                args.insert("tau".to_string(), tau);
248            }
249            let mut pred_hierarchy = VecDeque::from(vec![predicate.clone()]);
250            while let Some(pred) = pred_hierarchy.pop_front() {
251                for (arg_type, name) in pred.args() {
252                    if !args.contains_key(name) {
253                        let arg_tp = get_type_by_path(scp.as_ref(), arg_type)?;
254                        if let Some(class) = arg_tp.clone().as_class() {
255                            let instances = class.instances();
256                            if instances.is_empty() {
257                                return Err(RiddleError::RuntimeError(format!("No instances found for argument '{}' of type '{}'", name, class.full_name())));
258                            } else if instances.len() == 1 {
259                                args.insert(name.clone(), Slot::ObjectRef(instances[0]));
260                            } else {
261                                args.insert(name.clone(), scp.core().new_var(class, instances.as_slice())?);
262                            }
263                        } else {
264                            args.insert(name.clone(), arg_tp.new_instance());
265                        }
266                    }
267                }
268                for parent_path in pred.parents() {
269                    let (predicate_name, class_path) = parent_path.split_last().ok_or_else(|| RiddleError::RuntimeError("Empty parent predicate path".into()))?;
270                    let parent_predicate = if class_path.is_empty() {
271                        scp.get_predicate(predicate_name).ok_or_else(|| RiddleError::NotFound(format!("Predicate '{}' in parent path", predicate_name)))?
272                    } else {
273                        let class = get_type_by_path(scp.as_ref(), class_path)?.as_class().ok_or_else(|| RiddleError::NotAClass(format!("Type '{}' in parent path", class_path.join("."))))?;
274                        class.get_predicate(predicate_name).ok_or_else(|| RiddleError::NotFound(format!("Predicate '{}' in class '{}'", predicate_name, class.full_name())))?
275                    };
276                    pred_hierarchy.push_back(parent_predicate);
277                }
278            }
279            let atom = scp.core().new_atom(predicate, *is_fact, args);
280            env.set(name.clone(), Slot::AtomRef(atom));
281            Ok(())
282        }
283        Statement::Return { value } => {
284            let ret = evaluate(scp.as_ref(), env.clone(), value)?;
285            env.set("__return".to_string(), ret);
286            Ok(())
287        }
288    }
289}
290
291pub fn evaluate(scp: &dyn Scope, env: Rc<dyn Env>, expr: &Expr) -> Result<Slot, RiddleError> {
292    match expr {
293        Expr::Bool(bool) => Ok(scp.core().new_bool(*bool)),
294        Expr::Int(int) => Ok(scp.core().new_int(*int)),
295        Expr::Real(num, den) => Ok(scp.core().new_real(*num, *den)),
296        Expr::String(string) => Ok(scp.core().new_string(string)),
297        Expr::QualifiedId { ids } => get_var_by_path(scp.core().as_ref(), env.as_ref(), ids),
298        Expr::Sum { terms } => {
299            let evaluated_terms: Vec<Slot> = terms.iter().map(|t| evaluate(scp, env.clone(), t)).collect::<Result<_, _>>()?;
300            Ok(scp.core().sum(&evaluated_terms)?)
301        }
302        Expr::Opposite { term } => {
303            let evaluated_term = evaluate(scp, env, term)?;
304            Ok(scp.core().opposite(evaluated_term)?)
305        }
306        Expr::Not { term } => {
307            let evaluated_term = evaluate(scp, env, term)?;
308            match &evaluated_term {
309                Slot::Primitive(var) => {
310                    if let Ok(bool_expr) = var.clone().as_any().downcast::<BoolExpr>() {
311                        Ok(Slot::Primitive(Rc::new(BoolExpr::Not { var_type: Rc::downgrade(&scp.core().bool_type()), term: bool_expr })))
312                    } else {
313                        Err(RiddleError::RuntimeError(format!("Expected boolean expression, got {}", evaluated_term)))
314                    }
315                }
316                _ => Err(RiddleError::RuntimeError(format!("Expected a primitive variable for negation, got {}", evaluated_term))),
317            }
318        }
319        Expr::Mul { factors } => {
320            let evaluated_factors: Vec<Slot> = factors.iter().map(|f| evaluate(scp, env.clone(), f)).collect::<Result<_, _>>()?;
321            Ok(scp.core().mul(&evaluated_factors)?)
322        }
323        Expr::Div { left, right } => {
324            let evaluated_left = evaluate(scp, env.clone(), left)?;
325            let evaluated_right = evaluate(scp, env, right)?;
326            Ok(scp.core().div(evaluated_left, evaluated_right)?)
327        }
328        Expr::Function { name, args } => {
329            let args = args.iter().map(|a| evaluate(scp, env.clone(), a)).collect::<Result<Vec<_>, _>>()?;
330            let arg_types = args
331                .iter()
332                .map(|a| match a {
333                    Slot::Primitive(var) => Ok(var.var_type()),
334                    Slot::ObjectRef(obj_id) => Ok(scp.core().get_object(*obj_id).ok_or_else(|| RiddleError::NotFound(format!("Object {} not found", *obj_id)))?.var_type()),
335                    Slot::AtomRef(atom_id) => Ok(scp.core().get_atom(*atom_id).ok_or_else(|| RiddleError::NotFound(format!("Atom {} not found", *atom_id)))?.var_type()),
336                })
337                .collect::<Result<Vec<_>, _>>()?;
338            let (last, rest) = name.split_last().ok_or_else(|| RiddleError::RuntimeError("Empty function path".into()))?;
339            if rest.is_empty() {
340                if let Some(function) = scp.get_function(last, &arg_types) {
341                    let out = function.call(env, args)?;
342                    out.ok_or_else(|| RiddleError::RuntimeError(format!("Function '{}' with argument types ({}) did not return a value", last, arg_types.iter().map(|t| t.full_name()).collect::<Vec<_>>().join(", "))))
343                } else {
344                    Err(RiddleError::NotFound(format!("Function '{}' with argument types ({}) not found", last, arg_types.iter().map(|t| t.full_name()).collect::<Vec<_>>().join(", "))))
345                }
346            } else {
347                let var = get_var_by_path(scp.core().as_ref(), env.as_ref(), rest)?;
348                match &var {
349                    Slot::Primitive(_) => Err(RiddleError::NotAClass(format!("Variable '{}' in function path is a primitive variable, expected an object or atom for function call", rest.join(".")))),
350                    Slot::ObjectRef(obj_id) => {
351                        let obj = scp.core().get_object(*obj_id).ok_or_else(|| RiddleError::NotFound(format!("Object {} not found", *obj_id)))?;
352                        if let Some(function) = obj.class().get_function(last, &arg_types) {
353                            let out = function.call(obj.as_env().ok_or_else(|| RiddleError::NotAnEnvironment(format!("Object {} does not have an environment", *obj_id)))?, args)?;
354                            out.ok_or_else(|| RiddleError::RuntimeError(format!("Function '{}' with argument types ({}) did not return a value", last, arg_types.iter().map(|t| t.full_name()).collect::<Vec<_>>().join(", "))))
355                        } else {
356                            Err(RiddleError::NotFound(format!("Function '{}' with argument types ({}) not found in class '{}'", last, arg_types.iter().map(|t| t.full_name()).collect::<Vec<_>>().join(", "), obj.class().full_name())))
357                        }
358                    }
359                    Slot::AtomRef(atom_id) => Err(RiddleError::NotAClass(format!("Variable '{}' in function path is an atom {}, expected an object for function call", rest.join("."), *atom_id))),
360                }
361            }
362        }
363        Expr::Eq { left, right } => {
364            let evaluated_left = evaluate(scp, env.clone(), left)?;
365            let evaluated_right = evaluate(scp, env, right)?;
366            Ok(Slot::Primitive(Rc::new(BoolExpr::Eq {
367                var_type: Rc::downgrade(&scp.core().bool_type()),
368                left: evaluated_left,
369                right: evaluated_right,
370            })))
371        }
372        Expr::Neq { left, right } => {
373            let evaluated_left = evaluate(scp, env.clone(), left)?;
374            let evaluated_right = evaluate(scp, env, right)?;
375            Ok(Slot::Primitive(Rc::new(BoolExpr::Not {
376                var_type: Rc::downgrade(&scp.core().bool_type()),
377                term: Rc::new(BoolExpr::Eq {
378                    var_type: Rc::downgrade(&scp.core().bool_type()),
379                    left: evaluated_left,
380                    right: evaluated_right,
381                }),
382            })))
383        }
384        Expr::Lt { left, right } => {
385            let evaluated_left = evaluate(scp, env.clone(), left)?;
386            let evaluated_right = evaluate(scp, env, right)?;
387            Ok(Slot::Primitive(Rc::new(BoolExpr::Lt {
388                var_type: Rc::downgrade(&scp.core().bool_type()),
389                left: evaluated_left,
390                right: evaluated_right,
391            })))
392        }
393        Expr::Leq { left, right } => {
394            let evaluated_left = evaluate(scp, env.clone(), left)?;
395            let evaluated_right = evaluate(scp, env, right)?;
396            Ok(Slot::Primitive(Rc::new(BoolExpr::Leq {
397                var_type: Rc::downgrade(&scp.core().bool_type()),
398                left: evaluated_left,
399                right: evaluated_right,
400            })))
401        }
402        Expr::Geq { left, right } => {
403            let evaluated_left = evaluate(scp, env.clone(), left)?;
404            let evaluated_right = evaluate(scp, env, right)?;
405            Ok(Slot::Primitive(Rc::new(BoolExpr::Leq {
406                var_type: Rc::downgrade(&scp.core().bool_type()),
407                left: evaluated_right,
408                right: evaluated_left,
409            })))
410        }
411        Expr::Gt { left, right } => {
412            let evaluated_left = evaluate(scp, env.clone(), left)?;
413            let evaluated_right = evaluate(scp, env, right)?;
414            Ok(Slot::Primitive(Rc::new(BoolExpr::Lt {
415                var_type: Rc::downgrade(&scp.core().bool_type()),
416                left: evaluated_right,
417                right: evaluated_left,
418            })))
419        }
420        Expr::Or { terms } => {
421            let evaluated_terms: Vec<Rc<BoolExpr>> = terms
422                .iter()
423                .map(|t| match evaluate(scp, env.clone(), t)? {
424                    Slot::Primitive(var) => {
425                        if let Ok(bool_expr) = var.as_any().downcast::<BoolExpr>() {
426                            Ok(bool_expr)
427                        } else {
428                            Err(RiddleError::RuntimeError("Expected boolean expression in 'or' term".to_string()))
429                        }
430                    }
431                    _ => Err(RiddleError::RuntimeError("Expected boolean expression in 'or' term".to_string())),
432                })
433                .collect::<Result<_, _>>()?;
434            Ok(Slot::Primitive(Rc::new(BoolExpr::Or { var_type: Rc::downgrade(&scp.core().bool_type()), terms: evaluated_terms })))
435        }
436        Expr::And { terms } => {
437            let evaluated_terms: Vec<Rc<BoolExpr>> = terms
438                .iter()
439                .map(|t| match evaluate(scp, env.clone(), t)? {
440                    Slot::Primitive(var) => {
441                        if let Ok(bool_expr) = var.as_any().downcast::<BoolExpr>() {
442                            Ok(bool_expr)
443                        } else {
444                            Err(RiddleError::RuntimeError("Expected boolean expression in 'and' term".to_string()))
445                        }
446                    }
447                    _ => Err(RiddleError::RuntimeError("Expected boolean expression in 'and' term".to_string())),
448                })
449                .collect::<Result<_, _>>()?;
450            Ok(Slot::Primitive(Rc::new(BoolExpr::And { var_type: Rc::downgrade(&scp.core().bool_type()), terms: evaluated_terms })))
451        }
452        Expr::NewObject { class_name, args } => {
453            let class = get_type_by_path(scp, class_name)?.as_class().ok_or_else(|| RiddleError::NotAClass(class_name.join(".")))?;
454            let args = args.iter().map(|a| evaluate(scp, env.clone(), a)).collect::<Result<Vec<_>, _>>()?;
455            let arg_types = args
456                .iter()
457                .map(|a| match a {
458                    Slot::Primitive(var) => Ok(var.var_type()),
459                    Slot::ObjectRef(obj_id) => Ok(scp.core().get_object(*obj_id).ok_or_else(|| RiddleError::NotFound(format!("Object {} not found", *obj_id)))?.var_type()),
460                    Slot::AtomRef(atom_id) => Ok(scp.core().get_atom(*atom_id).ok_or_else(|| RiddleError::NotFound(format!("Atom {} not found", *atom_id)))?.var_type()),
461                })
462                .collect::<Result<Vec<_>, _>>()?;
463            let constructor = class.constructor(&arg_types).ok_or_else(|| RiddleError::NotFound(format!("Constructor for class '{}' with argument types ({}) not found", class.full_name(), arg_types.iter().map(|t| t.full_name()).collect::<Vec<_>>().join(", "))))?;
464            let object = class.new_instance();
465            let object = match object {
466                Slot::ObjectRef(obj_id) => Ok(obj_id),
467                _ => Err(RiddleError::RuntimeError("Constructor did not return an object reference".to_string())),
468            }?;
469            constructor.call(object, args)?;
470            Ok(Slot::ObjectRef(object))
471        }
472    }
473}