1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52

use crate::errors::err_not_a_context;
use dmntk_common::Result;
use dmntk_feel::context::FeelContext;
use dmntk_feel::values::Value;
use dmntk_feel::{AstNode, Evaluator, FeelType, Scope};

/// Evaluates a [Value] from given [AstNode].
pub fn evaluate(scope: &Scope, node: &AstNode) -> Result<Value> {
  let evaluator = crate::builders::build_evaluator(node)?;
  Ok(evaluator(scope))
}

/// Prepares an evaluator for given [AstNode].
pub fn prepare(node: &AstNode) -> Result<Evaluator> {
  crate::builders::build_evaluator(node)
}

/// Evaluates the sum of specified values.
pub fn evaluate_sum(values: Vec<Value>) -> Value {
  crate::bifs::core::sum(&values)
}

/// Evaluates the minimum value from specified values.
pub fn evaluate_min(values: Vec<Value>) -> Value {
  crate::bifs::core::min(&values)
}

/// Evaluates the maximum value from specified values.
pub fn evaluate_max(values: Vec<Value>) -> Value {
  crate::bifs::core::max(&values)
}

/// Evaluates the type of the AST node.
pub fn evaluate_node_type(scope: &Scope, node: &AstNode) -> FeelType {
  node.type_of(scope)
}

/// Compares two values and returns `true` when the two `FEEL` values are equal.
pub fn evaluate_equals(left: &Value, right: &Value) -> bool {
  crate::builders::eval_ternary_equality(left, right).unwrap_or(false)
}

/// Evaluates a context.
pub fn evaluate_context(scope: &Scope, input: &str) -> Result<FeelContext> {
  let node = &dmntk_feel_parser::parse_context(scope, input, false)?;
  let evaluator = crate::builders::build_evaluator(node)?;
  if let Value::Context(context) = evaluator(scope) {
    Ok(context)
  } else {
    Err(err_not_a_context())
  }
}