parse_and_validate_formula: Extract Symbols and Validate Formula AST

In GeoIndexR: Computation of Spectral and Geospatial Indices from Multispectral Raster Data

Extract Symbols and Validate Formula AST

Description

Recursively traverses the parsed formula AST to verify that only permitted mathematical operators, whitelisted mathematical functions, known spectral bands, and user-supplied parameters are present.

Usage

parse_and_validate_formula(
  formula_str,
  available_bands = character(0),
  param_names = character(0)
)

Arguments

formula_str	Character string containing the mathematical formula.
available_bands	Character vector of valid spectral band identifiers.
param_names	Character vector of valid parameter names.

Value

A list containing:

parsed_expr	The parsed R expression object.
used_bands	Character vector of band names referenced in the formula.
used_params	Character vector of parameter names referenced in the formula.

GeoIndexR documentation built on Oct. 10, 2026, 5:08 p.m.