rulemorph 0.3.4

YAML-based declarative data transformation engine for CSV/JSON to JSON
Documentation 
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use super::super::*;

pub(in crate::transform::operators) fn eval_array_reduce(
    args: &[Expr],
    injected: Option<&EvalValue>,
    record: &JsonValue,
    context: Option<&JsonValue>,
    out: &JsonValue,
    base_path: &str,
    locals: Option<&EvalLocals<'_>>,
) -> Result<EvalValue, TransformError> {
    let total_len = args_len(args, injected);
    if total_len != 2 {
        return Err(TransformError::new(
            TransformErrorKind::ExprError,
            "expr.args must contain exactly two items",
        )
        .with_path(format!("{}.args", base_path)));
    }

    let array = eval_array_arg(0, args, injected, record, context, out, base_path, locals)?;
    if array.is_empty() {
        return Ok(EvalValue::Value(JsonValue::Null));
    }

    let expr = arg_expr_at(1, args, injected).ok_or_else(|| {
        TransformError::new(
            TransformErrorKind::ExprError,
            "expr.args index is out of bounds",
        )
        .with_path(format!("{}.args[1]", base_path))
    })?;
    let expr_index = if injected.is_some() { 0 } else { 1 };
    let expr_path = format!("{}.args[{}]", base_path, expr_index);

    let mut acc = array[0].clone();
    for (index, item) in array.iter().enumerate().skip(1) {
        let item_locals = EvalLocals {
            item: Some(EvalItem { value: item, index }),
            acc: Some(&acc),
            pipe: locals.and_then(|locals| locals.pipe),
            locals: locals.and_then(|locals| locals.locals),
            precomputed_op_args: locals.and_then(|locals| locals.precomputed_op_args),
            limits: locals.map(|locals| locals.limits).unwrap_or_default(),
        };
        let value = eval_expr_or_null(expr, record, context, out, &expr_path, Some(&item_locals))?;
        acc = value;
    }

    Ok(EvalValue::Value(acc))
}

pub(in crate::transform::operators) fn eval_array_fold(
    args: &[Expr],
    injected: Option<&EvalValue>,
    record: &JsonValue,
    context: Option<&JsonValue>,
    out: &JsonValue,
    base_path: &str,
    locals: Option<&EvalLocals<'_>>,
) -> Result<EvalValue, TransformError> {
    let total_len = args_len(args, injected);
    if total_len != 3 {
        return Err(TransformError::new(
            TransformErrorKind::ExprError,
            "expr.args must contain exactly three items",
        )
        .with_path(format!("{}.args", base_path)));
    }

    let array = eval_array_arg(0, args, injected, record, context, out, base_path, locals)?;
    let initial =
        match eval_expr_at_index(1, args, injected, record, context, out, base_path, locals)? {
            EvalValue::Missing => return Ok(EvalValue::Missing),
            EvalValue::Value(value) => value,
        };

    let expr = arg_expr_at(2, args, injected).ok_or_else(|| {
        TransformError::new(
            TransformErrorKind::ExprError,
            "expr.args index is out of bounds",
        )
        .with_path(format!("{}.args[2]", base_path))
    })?;
    let expr_index = if injected.is_some() { 1 } else { 2 };
    let expr_path = format!("{}.args[{}]", base_path, expr_index);

    let mut acc = initial;
    for (index, item) in array.iter().enumerate() {
        let item_locals = EvalLocals {
            item: Some(EvalItem { value: item, index }),
            acc: Some(&acc),
            pipe: locals.and_then(|locals| locals.pipe),
            locals: locals.and_then(|locals| locals.locals),
            precomputed_op_args: locals.and_then(|locals| locals.precomputed_op_args),
            limits: locals.map(|locals| locals.limits).unwrap_or_default(),
        };
        let value = eval_expr_or_null(expr, record, context, out, &expr_path, Some(&item_locals))?;
        acc = value;
    }

    Ok(EvalValue::Value(acc))
}