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Add eval function.

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This commit is contained in:
Stephen Chung
2020-03-19 19:53:42 +08:00
parent cc8ec12691
commit 6a6c5f30de
6 changed files with 229 additions and 93 deletions
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108
src/engine.rs
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@@ -38,6 +38,7 @@ pub(crate) const KEYWORD_PRINT: &'static str = "print";
pub(crate) const KEYWORD_DEBUG: &'static str = "debug";
pub(crate) const KEYWORD_DUMP_AST: &'static str = "dump_ast";
pub(crate) const KEYWORD_TYPE_OF: &'static str = "type_of";
pub(crate) const KEYWORD_EVAL: &'static str = "eval";
pub(crate) const FUNC_GETTER: &'static str = "get$";
pub(crate) const FUNC_SETTER: &'static str = "set$";
@@ -160,6 +161,7 @@ impl Engine<'_> {
/// registered with the `Engine` or written in Rhai
pub(crate) fn call_fn_raw(
&mut self,
scope: &mut Scope,
fn_name: &str,
args: FnCallArgs,
def_val: Option<&Dynamic>,
@@ -185,10 +187,15 @@ impl Engine<'_> {
// Evaluate
// Convert return statement to return value
return match self.eval_stmt(&mut scope, &fn_def.body) {
Err(EvalAltResult::Return(x, _)) => Ok(x),
other => other,
};
return self
.eval_stmt(&mut scope, &fn_def.body)
.or_else(|mut err| match err {
EvalAltResult::Return(x, _) => Ok(x),
_ => {
err.set_position(pos);
Err(err)
}
});
}
let spec = FnSpec {
@@ -196,24 +203,26 @@ impl Engine<'_> {
args: Some(args.iter().map(|a| Any::type_id(&**a)).collect()),
};
// Argument must be a string
fn cast_to_string<'a>(r: &'a Variant, pos: Position) -> Result<&'a str, EvalAltResult> {
r.downcast_ref::<String>()
.map(String::as_str)
.ok_or_else(|| EvalAltResult::ErrorMismatchOutputType(r.type_name().into(), pos))
}
// Search built-in's and external functions
if let Some(func) = self.ext_functions.get(&spec) {
// Run external function
let result = func(args, pos)?;
// See if the function match print/debug (which requires special processing)
let callback = match fn_name {
KEYWORD_PRINT => self.on_print.as_mut(),
KEYWORD_DEBUG => self.on_debug.as_mut(),
_ => return Ok(result),
};
match fn_name {
KEYWORD_PRINT => self.on_print.as_mut()(cast_to_string(result.as_ref(), pos)?),
KEYWORD_DEBUG => self.on_debug.as_mut()(cast_to_string(result.as_ref(), pos)?),
_ => (),
}
let val = &result
.downcast::<String>()
.map(|s| *s)
.unwrap_or("error: not a string".into());
return Ok(callback(val).into_dynamic());
return Ok(result);
}
if fn_name == KEYWORD_TYPE_OF && args.len() == 1 {
@@ -224,6 +233,32 @@ impl Engine<'_> {
.into_dynamic());
}
if fn_name == KEYWORD_EVAL && args.len() == 1 {
// Handle `eval` function
let script = cast_to_string(args[0], pos)?;
#[cfg(not(feature = "no_optimize"))]
let ast = {
let orig_optimization_level = self.optimization_level;
self.set_optimization_level(OptimizationLevel::None);
let ast = self.compile(script);
self.set_optimization_level(orig_optimization_level);
ast.map_err(EvalAltResult::ErrorParsing)?
};
#[cfg(feature = "no_optimize")]
let ast = self.compile(script).map_err(EvalAltResult::ErrorParsing)?;
return Ok(self
.eval_ast_with_scope_raw(scope, true, &ast)
.map_err(|mut err| {
err.set_position(pos);
err
})?);
}
if fn_name.starts_with(FUNC_GETTER) {
// Getter function not found
return Err(EvalAltResult::ErrorDotExpr(
@@ -283,14 +318,14 @@ impl Engine<'_> {
.chain(values.iter_mut().map(Dynamic::as_mut))
.collect();
self.call_fn_raw(fn_name, args, def_val.as_ref(), *pos)
self.call_fn_raw(scope, fn_name, args, def_val.as_ref(), *pos)
}
// xxx.id
Expr::Property(id, pos) => {
let get_fn_name = format!("{}{}", FUNC_GETTER, id);
self.call_fn_raw(&get_fn_name, vec![this_ptr], None, *pos)
self.call_fn_raw(scope, &get_fn_name, vec![this_ptr], None, *pos)
}
// xxx.idx_lhs[idx_expr]
@@ -301,7 +336,7 @@ impl Engine<'_> {
Expr::Property(id, pos) => {
let get_fn_name = format!("{}{}", FUNC_GETTER, id);
(
self.call_fn_raw(&get_fn_name, vec![this_ptr], None, *pos)?,
self.call_fn_raw(scope, &get_fn_name, vec![this_ptr], None, *pos)?,
*pos,
)
}
@@ -329,7 +364,7 @@ impl Engine<'_> {
Expr::Property(id, pos) => {
let get_fn_name = format!("{}{}", FUNC_GETTER, id);
self.call_fn_raw(&get_fn_name, vec![this_ptr], None, *pos)
self.call_fn_raw(scope, &get_fn_name, vec![this_ptr], None, *pos)
.and_then(|mut v| self.get_dot_val_helper(scope, v.as_mut(), rhs))
}
// xxx.idx_lhs[idx_expr].rhs
@@ -340,7 +375,7 @@ impl Engine<'_> {
Expr::Property(id, pos) => {
let get_fn_name = format!("{}{}", FUNC_GETTER, id);
(
self.call_fn_raw(&get_fn_name, vec![this_ptr], None, *pos)?,
self.call_fn_raw(scope, &get_fn_name, vec![this_ptr], None, *pos)?,
*pos,
)
}
@@ -642,7 +677,13 @@ impl Engine<'_> {
Expr::Property(id, pos) => {
let set_fn_name = format!("{}{}", FUNC_SETTER, id);
self.call_fn_raw(&set_fn_name, vec![this_ptr, new_val.as_mut()], None, *pos)
self.call_fn_raw(
scope,
&set_fn_name,
vec![this_ptr, new_val.as_mut()],
None,
*pos,
)
}
// xxx.lhs[idx_expr]
@@ -653,14 +694,20 @@ impl Engine<'_> {
Expr::Property(id, pos) => {
let get_fn_name = format!("{}{}", FUNC_GETTER, id);
self.call_fn_raw(&get_fn_name, vec![this_ptr], None, *pos)
self.call_fn_raw(scope, &get_fn_name, vec![this_ptr], None, *pos)
.and_then(|v| {
let idx = self.eval_index_value(scope, idx_expr)?;
Self::update_indexed_value(v, idx as usize, new_val, val_pos)
})
.and_then(|mut v| {
let set_fn_name = format!("{}{}", FUNC_SETTER, id);
self.call_fn_raw(&set_fn_name, vec![this_ptr, v.as_mut()], None, *pos)
self.call_fn_raw(
scope,
&set_fn_name,
vec![this_ptr, v.as_mut()],
None,
*pos,
)
})
}
@@ -677,7 +724,7 @@ impl Engine<'_> {
Expr::Property(id, pos) => {
let get_fn_name = format!("{}{}", FUNC_GETTER, id);
self.call_fn_raw(&get_fn_name, vec![this_ptr], None, *pos)
self.call_fn_raw(scope, &get_fn_name, vec![this_ptr], None, *pos)
.and_then(|mut v| {
self.set_dot_val_helper(scope, v.as_mut(), rhs, new_val, val_pos)
.map(|_| v) // Discard Ok return value
@@ -685,7 +732,13 @@ impl Engine<'_> {
.and_then(|mut v| {
let set_fn_name = format!("{}{}", FUNC_SETTER, id);
self.call_fn_raw(&set_fn_name, vec![this_ptr, v.as_mut()], None, *pos)
self.call_fn_raw(
scope,
&set_fn_name,
vec![this_ptr, v.as_mut()],
None,
*pos,
)
})
}
@@ -697,7 +750,7 @@ impl Engine<'_> {
Expr::Property(id, pos) => {
let get_fn_name = format!("{}{}", FUNC_GETTER, id);
self.call_fn_raw(&get_fn_name, vec![this_ptr], None, *pos)
self.call_fn_raw(scope, &get_fn_name, vec![this_ptr], None, *pos)
.and_then(|v| {
let idx = self.eval_index_value(scope, idx_expr)?;
let (mut target, _) =
@@ -718,6 +771,7 @@ impl Engine<'_> {
let set_fn_name = format!("{}{}", FUNC_SETTER, id);
self.call_fn_raw(
scope,
&set_fn_name,
vec![this_ptr, v.as_mut()],
None,
@@ -936,6 +990,7 @@ impl Engine<'_> {
// Redirect call to `print`
self.call_fn_raw(
scope,
KEYWORD_PRINT,
vec![result.into_dynamic().as_mut()],
None,
@@ -951,6 +1006,7 @@ impl Engine<'_> {
.collect::<Result<Vec<Dynamic>, _>>()?;
self.call_fn_raw(
scope,
fn_name,
values.iter_mut().map(|b| b.as_mut()).collect(),
def_val.as_ref(),