/**
 * Returns the possible types for a given value (each type being a binary flag)
 * To test a value use e.g. `getValueType(v) & ValueTypes.BOOLEAN`
 * @param {ExpressionValue} value Value
 * @return {ValueTypes|number} Type or types inferred from the value
 */
export function getValueType(value: ExpressionValue): ValueTypes | number;
/**
 * Checks if only one value type is enabled in the input number.
 * @param {ValueTypes|number} valueType Number containing value type binary flags
 * @return {boolean} True if only one type flag is enabled, false if zero or multiple
 */
export function isTypeUnique(valueType: ValueTypes | number): boolean;
/**
 * Will return the number as a float with a dot separator, which is required by GLSL.
 * @param {number} v Numerical value.
 * @return {string} The value as string.
 */
export function numberToGlsl(v: number): string;
/**
 * Will return the number array as a float with a dot separator, concatenated with ', '.
 * @param {Array<number>} array Numerical values array.
 * @return {string} The array as a vector, e. g.: `vec3(1.0, 2.0, 3.0)`.
 */
export function arrayToGlsl(array: Array<number>): string;
/**
 * Will normalize and converts to string a `vec4` color array compatible with GLSL.
 * @param {string|import("../color.js").Color} color Color either in string format or [r, g, b, a] array format,
 * with RGB components in the 0..255 range and the alpha component in the 0..1 range.
 * Note that the final array will always have 4 components.
 * @return {string} The color expressed in the `vec4(1.0, 1.0, 1.0, 1.0)` form.
 */
export function colorToGlsl(color: string | import("../color.js").Color): string;
/**
 * Returns a stable equivalent number for the string literal.
 * @param {ParsingContext} context Parsing context
 * @param {string} string String literal value
 * @return {number} Number equivalent
 */
export function getStringNumberEquivalent(context: ParsingContext, string: string): number;
/**
 * Returns a stable equivalent number for the string literal, for use in shaders. This number is then
 * converted to be a GLSL-compatible string.
 * @param {ParsingContext} context Parsing context
 * @param {string} string String literal value
 * @return {string} GLSL-compatible string containing a number
 */
export function stringToGlsl(context: ParsingContext, string: string): string;
/**
 * Recursively parses a style expression and outputs a GLSL-compatible string. Takes in a parsing context that
 * will be read and modified during the parsing operation.
 * @param {ParsingContext} context Parsing context
 * @param {ExpressionValue} value Value
 * @param {ValueTypes|number} [expectedType] Expected final type (can be several types combined)
 * If omitted, defaults to ValueTypes.NUMBER
 * @return {string} GLSL-compatible output
 */
export function expressionToGlsl(context: ParsingContext, value: ExpressionValue, expectedType?: number | undefined): string;
/**
 * Get the uniform name given a variable name.
 * @param {string} variableName The variable name.
 * @return {string} The uniform name.
 */
export function uniformNameForVariable(variableName: string): string;
/**
 * Possible inferred types from a given value or expression.
 * Note: these are binary flags.
 */
export type ValueTypes = number;
export namespace ValueTypes {
    let NUMBER: number;
    let STRING: number;
    let COLOR: number;
    let BOOLEAN: number;
    let NUMBER_ARRAY: number;
    let ANY: number;
    let NONE: number;
}
/**
 * An operator declaration must contain two methods: `getReturnType` which returns a type based on
 * the operator arguments, and `toGlsl` which returns a GLSL-compatible string.
 * Note: both methods can process arguments recursively.
 * @typedef {Object} Operator
 * @property {function(Array<ExpressionValue>): ValueTypes|number} getReturnType Returns one or several types
 * @property {function(ParsingContext, Array<ExpressionValue>, ValueTypes): string} toGlsl Returns a GLSL-compatible string
 * given a parsing context, an array of arguments and an expected type.
 * Note: the expected type can be a combination such as ValueTypes.NUMBER | ValueTypes.STRING or ValueTypes.ANY for instance
 */
/**
 * Operator declarations
 * @type {Object<string, Operator>}
 */
export const Operators: {
    [x: string]: Operator;
};
export const PALETTE_TEXTURE_ARRAY: "u_paletteTextures";
export type ParsingContextExternal = {
    /**
     * Name, unprefixed
     */
    name: string;
    /**
     * One of the value types constants
     */
    type: ValueTypes;
    /**
     * Function used for computing the attribute value;
     * if undefined, `feature.get(attribute.name)` will be used
     */
    callback?: ((arg0: import("../Feature.js").FeatureLike) => any) | undefined;
};
/**
 * Context available during the parsing of an expression.
 */
export type ParsingContext = {
    /**
     * If false, means the expression output should be made for a vertex shader
     */
    inFragmentShader?: boolean | undefined;
    /**
     * External variables used in the expression
     */
    variables: Array<ParsingContextExternal>;
    /**
     * External attributes used in the expression
     */
    attributes: Array<ParsingContextExternal>;
    /**
     * This object maps all encountered string values to a number
     */
    stringLiteralsMap: {
        [x: string]: number;
    };
    /**
     * Lookup of functions used by the style.
     */
    functions: {
        [x: string]: string;
    };
    /**
     * Number of bands per pixel.
     */
    bandCount?: number | undefined;
    /**
     * List of palettes used by the style.
     */
    paletteTextures?: PaletteTexture[] | undefined;
    /**
     * The style being parsed
     */
    style: import("../style/literal").LiteralStyle;
};
/**
 * Base type used for literal style parameters; can be a number literal or the output of an operator,
 * which in turns takes {@link import ("./expressions.js").ExpressionValue} arguments.
 *
 * The following operators can be used:
 *
 * * Reading operators:
 *   * `['band', bandIndex, xOffset, yOffset]` For tile layers only. Fetches pixel values from band
 *     `bandIndex` of the source's data. The first `bandIndex` of the source data is `1`. Fetched values
 *     are in the 0..1 range. {@link import ("../source/TileImage.js").default} sources have 4 bands: red,
 *     green, blue and alpha. {@link import ("../source/DataTile.js").default} sources can have any number
 *     of bands, depending on the underlying data source and
 *     {@link import ("../source/GeoTIFF.js").Options configuration}. `xOffset` and `yOffset` are optional
 *     and allow specifying pixel offsets for x and y. This is used for sampling data from neighboring pixels.
 *   * `['get', 'attributeName', typeHint]` fetches a feature property value, similar to `feature.get('attributeName')`
 *     A type hint can optionally be specified, in case the resulting expression contains a type ambiguity which
 *     will make it invalid. Type hints can be one of: 'string', 'color', 'number', 'boolean', 'number[]'
 *   * `['geometry-type']` returns a feature's geometry type as string, either: 'LineString', 'Point' or 'Polygon'
 *     `Multi*` values are returned as their singular equivalent
 *     `Circle` geometries are returned as 'Polygon'
 *     `GeometryCollection` geometries are returned as the type of the first geometry found in the collection
 *   * `['resolution']` returns the current resolution
 *   * `['time']` returns the time in seconds since the creation of the layer
 *   * `['var', 'varName']` fetches a value from the style variables; will throw an error if that variable is undefined
 *   * `['zoom']` returns the current zoom level
 *
 * * Math operators:
 *   * `['*', value1, value2, ...]` multiplies the values (either numbers or colors)
 *   * `['/', value1, value2]` divides `value1` by `value2`
 *   * `['+', value1, value2, ...]` adds the values
 *   * `['-', value1, value2]` subtracts `value2` from `value1`
 *   * `['clamp', value, low, high]` clamps `value` between `low` and `high`
 *   * `['%', value1, value2]` returns the result of `value1 % value2` (modulo)
 *   * `['^', value1, value2]` returns the value of `value1` raised to the `value2` power
 *   * `['abs', value1]` returns the absolute value of `value1`
 *   * `['floor', value1]` returns the nearest integer less than or equal to `value1`
 *   * `['round', value1]` returns the nearest integer to `value1`
 *   * `['ceil', value1]` returns the nearest integer greater than or equal to `value1`
 *   * `['sin', value1]` returns the sine of `value1`
 *   * `['cos', value1]` returns the cosine of `value1`
 *   * `['atan', value1, value2]` returns `atan2(value1, value2)`. If `value2` is not provided, returns `atan(value1)`
 *   * `['sqrt', value1]` returns the square root of `value1`
 *
 * * Transform operators:
 *   * `['case', condition1, output1, ...conditionN, outputN, fallback]` selects the first output whose corresponding
 *     condition evaluates to `true`. If no match is found, returns the `fallback` value.
 *     All conditions should be `boolean`, output and fallback can be any kind.
 *   * `['match', input, match1, output1, ...matchN, outputN, fallback]` compares the `input` value against all
 *     provided `matchX` values, returning the output associated with the first valid match. If no match is found,
 *     returns the `fallback` value.
 *     `input` and `matchX` values must all be of the same type, and can be `number` or `string`. `outputX` and
 *     `fallback` values must be of the same type, and can be of any kind.
 *   * `['interpolate', interpolation, input, stop1, output1, ...stopN, outputN]` returns a value by interpolating between
 *     pairs of inputs and outputs; `interpolation` can either be `['linear']` or `['exponential', base]` where `base` is
 *     the rate of increase from stop A to stop B (i.e. power to which the interpolation ratio is raised); a value
 *     of 1 is equivalent to `['linear']`.
 *     `input` and `stopX` values must all be of type `number`. `outputX` values can be `number` or `color` values.
 *     Note: `input` will be clamped between `stop1` and `stopN`, meaning that all output values will be comprised
 *     between `output1` and `outputN`.
 *
 * * Logical operators:
 *   * `['<', value1, value2]` returns `true` if `value1` is strictly lower than `value2`, or `false` otherwise.
 *   * `['<=', value1, value2]` returns `true` if `value1` is lower than or equals `value2`, or `false` otherwise.
 *   * `['>', value1, value2]` returns `true` if `value1` is strictly greater than `value2`, or `false` otherwise.
 *   * `['>=', value1, value2]` returns `true` if `value1` is greater than or equals `value2`, or `false` otherwise.
 *   * `['==', value1, value2]` returns `true` if `value1` equals `value2`, or `false` otherwise.
 *   * `['!=', value1, value2]` returns `true` if `value1` does not equal `value2`, or `false` otherwise.
 *   * `['!', value1]` returns `false` if `value1` is `true` or greater than `0`, or `true` otherwise.
 *   * `['all', value1, value2, ...]` returns `true` if all the inputs are `true`, `false` otherwise.
 *   * `['any', value1, value2, ...]` returns `true` if any of the inputs are `true`, `false` otherwise.
 *   * `['between', value1, value2, value3]` returns `true` if `value1` is contained between `value2` and `value3`
 *     (inclusively), or `false` otherwise.
 *   * `['in', needle, haystack]` returns `true` if `needle` is found in `haystack`, and
 *     `false` otherwise.
 *     This operator has the following limitations:
 *     * `haystack` has to be an array of numbers or strings (searching for a substring in a string is not supported yet)
 *     * Only literal arrays are supported as `haystack` for now; this means that `haystack` cannot be the result of an
 *     expression. If `haystack` is an array of strings, use the `literal` operator to disambiguate from an expression:
 *     `['literal', ['abc', 'def', 'ghi']]`
 *
 * * Conversion operators:
 *   * `['array', value1, ...valueN]` creates a numerical array from `number` values; please note that the amount of
 *     values can currently only be 2, 3 or 4.
 *   * `['color', red, green, blue, alpha]` creates a `color` value from `number` values; the `alpha` parameter is
 *     optional; if not specified, it will be set to 1.
 *     Note: `red`, `green` and `blue` components must be values between 0 and 255; `alpha` between 0 and 1.
 *   * `['palette', index, colors]` picks a `color` value from an array of colors using the given index; the `index`
 *     expression must evaluate to a number; the items in the `colors` array must be strings with hex colors
 *     (e.g. `'#86A136'`), colors using the rgba[a] functional notation (e.g. `'rgb(134, 161, 54)'` or `'rgba(134, 161, 54, 1)'`),
 *     named colors (e.g. `'red'`), or array literals with 3 ([r, g, b]) or 4 ([r, g, b, a]) values (with r, g, and b
 *     in the 0-255 range and a in the 0-1 range).
 *
 * Values can either be literals or another operator, as they will be evaluated recursively.
 * Literal values can be of the following types:
 * * `boolean`
 * * `number`
 * * `number[]` (number arrays can only have a length of 2, 3 or 4)
 * * `string`
 * * {@link module :ol/color~Color}
 */
export type ExpressionValue = Array<any> | import("../color.js").Color | string | number | boolean;
/**
 * An operator declaration must contain two methods: `getReturnType` which returns a type based on
 * the operator arguments, and `toGlsl` which returns a GLSL-compatible string.
 * Note: both methods can process arguments recursively.
 */
export type Operator = {
    /**
     * Returns one or several types
     */
    getReturnType: (arg0: Array<ExpressionValue>) => ValueTypes | number;
    /**
     * Returns a GLSL-compatible string
     * given a parsing context, an array of arguments and an expected type.
     * Note: the expected type can be a combination such as ValueTypes.NUMBER | ValueTypes.STRING or ValueTypes.ANY for instance
     */
    toGlsl: (arg0: ParsingContext, arg1: Array<ExpressionValue>, arg2: ValueTypes) => string;
};
import PaletteTexture from '../webgl/PaletteTexture.js';
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