/**
 * Validation for `<gen type="formula">` — a column computed from its own row.
 *
 * Three things have to be true before a formula can run, and all three are
 * knowable from the config alone, so all three are refused by `check` rather
 * than by the run:
 *
 *   1. it says WHAT to compute — `expr=` is there and parses;
 *   2. every NAME in it is a sequence, not a typo;
 *   3. every one of those is declared ABOVE it, because a formula is built in
 *      declaration order out of columns that already exist.
 *
 * Rule 3 borrows TDC240 from `running` and `stat` on purpose — same rule, same
 * fix, and a third code for it would lengthen the error reference without
 * telling a reader anything new.
 *
 * Rule 2 is the one that matters most in practice. An unknown name in an `if=`
 * is a bare WORD and the branch quietly stops firing; in a formula the same
 * typo reaches arithmetic, and `Heigth * 2` is NaN. Left to the run that prints
 * as a refusal on row one — after `check` has already called the config valid,
 * which is the failure this project keeps closing.
 */
import jsep from 'jsep';
import type { Diagnostic } from '../errors/index.js';
import type { OpenCloseElementContext, SelfClosingElementContext } from '../generated/TDCParser.js';
/** Everything a formula cannot do without, and the names it is allowed to read. */
export declare function checkGenFormula(gen: OpenCloseElementContext | SelfClosingElementContext, declaredAbove: readonly string[], diagnostics: Diagnostic[], 
/** The sequence this formula belongs to — the one name `prev()` may add. */
ownName?: string): void;
/**
 * Every NAME the expression reads.
 *
 * A formula has no bare-word case to protect: `if="Gender == Male"` needs
 * `Male` to stay a word, but nothing is compared here — the whole expression is
 * arithmetic whose answer is printed. So every identifier is a column
 * reference, and one that is not a column is a typo rather than a word.
 *
 * The one exception is the branches of a ternary, which is how a formula writes
 * a LABEL — `expr="BMI > 25 ? over : normal"`. Those two are words on purpose,
 * so they are skipped, exactly as the right-hand side of a comparison is.
 */
export declare function identifiersOf(node: jsep.Expression): string[];
/**
 * Does this expression call `prev()` at all?
 *
 * A formula that does reads the row before its own, so it is built in row order
 * over the whole run — a whole column, like a running total. Text that does not
 * parse answers no: TDC294 already reports it, and one wrong config deserves one
 * diagnostic.
 */
export declare function callsPrev(expr: string): boolean;
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