uqa-sql 0.3.6

PostgreSQL-compatible SQL compiler built on libpg_query
Documentation 
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//
// Unified Query Algebra
//
// Copyright (c) 2023-2026 Cognica, Inc.
//

//! Row-independent mutation input shapes.
use crate::ScalarExpr;

pub fn top_level_column(expr: &ScalarExpr) -> Option<&str> {
    match expr {
        ScalarExpr::Column(name) => Some(name),
        ScalarExpr::QualifiedColumn { column, .. } => Some(column),
        _ => None,
    }
}

pub fn expr_is_row_independent(expr: &ScalarExpr) -> bool {
    match expr {
        ScalarExpr::Literal(_) | ScalarExpr::TypedLiteral { .. } | ScalarExpr::Param(_) => true,
        ScalarExpr::Array(items)
        | ScalarExpr::Row(items)
        | ScalarExpr::And(items)
        | ScalarExpr::Or(items) => items.iter().all(expr_is_row_independent),
        ScalarExpr::Binary { lhs, rhs, .. } => {
            expr_is_row_independent(lhs) && expr_is_row_independent(rhs)
        }
        ScalarExpr::Not(inner) | ScalarExpr::UnaryMinus(inner) => expr_is_row_independent(inner),
        ScalarExpr::IsNull { expr, .. } => expr_is_row_independent(expr),
        ScalarExpr::Between { expr, low, high } => {
            expr_is_row_independent(expr)
                && expr_is_row_independent(low)
                && expr_is_row_independent(high)
        }
        ScalarExpr::InList { expr, list, .. } => {
            expr_is_row_independent(expr) && list.iter().all(expr_is_row_independent)
        }
        ScalarExpr::Case {
            base,
            when,
            else_branch,
        } => {
            base.as_deref().map_or(true, expr_is_row_independent)
                && when.iter().all(|(condition, result)| {
                    expr_is_row_independent(condition) && expr_is_row_independent(result)
                })
                && else_branch.as_deref().map_or(true, expr_is_row_independent)
        }
        ScalarExpr::Cast { expr, .. } => expr_is_row_independent(expr),
        ScalarExpr::Default
        | ScalarExpr::Star
        | ScalarExpr::QualifiedStar(_)
        | ScalarExpr::Column(_)
        | ScalarExpr::Position(_)
        | ScalarExpr::InternalColumn(_)
        | ScalarExpr::QualifiedColumn { .. }
        | ScalarExpr::Func { .. }
        | ScalarExpr::WindowCall { .. }
        | ScalarExpr::ScalarSubquery(_)
        | ScalarExpr::Exists { .. }
        | ScalarExpr::InSubquery { .. } => false,
    }
}