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//! Normalising rules for `Sum`
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use conjure_core::ast::Expression as Expr;

            

        

            

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use conjure_core::rule_engine::{register_rule, ApplicationError, ApplicationResult, Reduction};

            

        

            

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use Expr::*;

            

        

            

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use crate::ast::SymbolTable;

            

        

            

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/// Removes sums with a single argument.

            

        

            

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///

            

        

            

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/// ```text

            

        

            

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/// sum([a]) ~> a

            

        

            

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/// ```

            

        

            

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#[register_rule(("Base", 8800))]

            

        

            

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fn remove_unit_vector_sum(expr: &Expr, _: &SymbolTable) -> ApplicationResult {

            

        

            

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    match expr {

            

        

            

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        Sum(_, exprs) if (exprs.len() == 1) => Ok(Reduction::pure(exprs[0].clone())),

            

        

            

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        _ => Err(ApplicationError::RuleNotApplicable),

            

        

            

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    }

            

        

            

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}