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Merge pull request #77 from stevedonovan/master

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Engine::register_type_name for nice error messages for arbitrary types
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Lukáš Hozda [magnusi] 2018-07-22 19:14:48 +02:00 committed by GitHub
commit 3bab79f375
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1 changed files with 30 additions and 25 deletions
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55
src/engine.rs
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@ -22,7 +22,7 @@ pub enum EvalAltResult {
ErrorVariableNotFound(String),
ErrorFunctionArityNotSupported,
ErrorAssignmentToUnknownLHS,
ErrorMismatchOutputType,
ErrorMismatchOutputType(String),
ErrorCantOpenScriptFile,
InternalErrorMalformedDotExpression,
LoopBreak,
@ -34,6 +34,7 @@ impl EvalAltResult {
match *self {
EvalAltResult::ErrorVariableNotFound(ref s) => Some(s.as_str()),
EvalAltResult::ErrorFunctionNotFound(ref s) => Some(s.as_str()),
EvalAltResult::ErrorMismatchOutputType(ref s) => Some(s.as_str()),
_ => None
}
}
@ -52,7 +53,7 @@ impl PartialEq for EvalAltResult {
(&ErrorVariableNotFound(ref a), &ErrorVariableNotFound(ref b)) => a == b,
(&ErrorFunctionArityNotSupported, &ErrorFunctionArityNotSupported) => true,
(&ErrorAssignmentToUnknownLHS, &ErrorAssignmentToUnknownLHS) => true,
(&ErrorMismatchOutputType, &ErrorMismatchOutputType) => true,
(&ErrorMismatchOutputType(ref a), &ErrorMismatchOutputType(ref b)) => a == b,
(&ErrorCantOpenScriptFile, &ErrorCantOpenScriptFile) => true,
(&InternalErrorMalformedDotExpression, &InternalErrorMalformedDotExpression) => true,
(&LoopBreak, &LoopBreak) => true,
@ -78,7 +79,7 @@ impl Error for EvalAltResult {
EvalAltResult::ErrorAssignmentToUnknownLHS => {
"Assignment to an unsupported left-hand side"
}
EvalAltResult::ErrorMismatchOutputType => "Cast of output failed",
EvalAltResult::ErrorMismatchOutputType(_) => "Cast of output failed",
EvalAltResult::ErrorCantOpenScriptFile => "Cannot open script file",
EvalAltResult::InternalErrorMalformedDotExpression => {
"[Internal error] Unexpected expression in dot expression"
@ -127,6 +128,7 @@ pub struct FnSpec {
pub struct Engine {
/// A hashmap containing all functions known to the engine
pub fns: HashMap<FnSpec, Arc<FnIntExt>>,
pub type_names: HashMap<TypeId,String>,
}
pub enum FnIntExt {
@ -163,7 +165,7 @@ impl Engine {
.and_then(|b| {
b.downcast()
.map(|b| *b)
.map_err(|_| EvalAltResult::ErrorMismatchOutputType)
.map_err(|a| EvalAltResult::ErrorMismatchOutputType(self.nice_type_name(a)))
})
}
@ -228,6 +230,13 @@ impl Engine {
// currently a no-op, exists for future extensibility
}
/// Register a type, providing a name for nice error messages.
pub fn register_type_name<T: Any>(&mut self, name: &str) {
self.register_type::<T>();
debug_println!("register type {}: {:?}", name, TypeId::of::<T>());
self.type_names.insert(TypeId::of::<T>(), name.into());
}
/// Register a get function for a member of a registered type
pub fn register_get<T: Clone + Any, U: Clone + Any, F>(&mut self, name: &str, get_fn: F)
where
@ -613,17 +622,9 @@ impl Engine {
}
fn nice_type_name(&self, b: Box<Any>) -> String {
if b.is::<String>() {
"string".into()
} else
if b.is::<i64>() {
"integer".into()
} else
if b.is::<f64>() {
"float".into()
} else
if b.is::<Vec<Box<Any>>>() {
"array".into()
let tid = (&*b).type_id();
if let Some(name) = self.type_names.get(&tid) {
name.to_string()
} else {
format!("<unknown> {:?}", b.type_id())
}
@ -692,7 +693,7 @@ impl Engine {
match x.downcast::<T>() {
Ok(out) => Ok(*out),
Err(_) => Err(EvalAltResult::ErrorMismatchOutputType),
Err(a) => Err(EvalAltResult::ErrorMismatchOutputType(self.nice_type_name(a))),
}
}
Err(_) => Err(EvalAltResult::ErrorFunctionArgMismatch),
@ -775,15 +776,17 @@ impl Engine {
/// Register the default library. That means, numberic types, char, bool
/// String, arithmetics and string concatenations.
pub fn register_default_lib(engine: &mut Engine) {
engine.register_type::<i32>();
engine.register_type::<u32>();
engine.register_type::<i64>();
engine.register_type::<u64>();
engine.register_type::<f32>();
engine.register_type::<f64>();
engine.register_type::<String>();
engine.register_type::<char>();
engine.register_type::<bool>();
engine.register_type_name::<i32>("i32");
engine.register_type_name::<u32>("u32");
engine.register_type_name::<i64>("integer");
engine.register_type_name::<u64>("u64");
engine.register_type_name::<u64>("usize");
engine.register_type_name::<f32>("f64");
engine.register_type_name::<f64>("float");
engine.register_type_name::<String>("string");
engine.register_type_name::<char>("char");
engine.register_type_name::<bool>("boolean");
engine.register_type_name::<Vec<Box<Any>>>("array");
macro_rules! reg_op {
($engine:expr, $x:expr, $op:expr, $( $y:ty ),*) => (
@ -871,12 +874,14 @@ impl Engine {
// FIXME? Registering array lookups are a special case because we want to return boxes
// directly let ent = engine.fns.entry("[]".to_string()).or_insert_with(Vec::new);
// (*ent).push(FnType::ExternalFn2(Box::new(idx)));
}
/// Make a new engine
pub fn new() -> Engine {
let mut engine = Engine {
fns: HashMap::new(),
type_names: HashMap::new(),
};
Engine::register_default_lib(&mut engine);