PK_EXPR_sf_t

struct PK_EXPR_sf_s
    {
    const char      *root_expr;      --- root expression definition (NULL)
    int              n_sub_exprs;    --- number of sub-expressions (0)
    const char     **sub_expr_names; --- sub-expression names (NULL)
    const char     **sub_expr_defs;  --- sub-expression definitions (NULL)
    int              n_consts;       --- number of application constants (0)
    const char     **const_names;    --- constant names (NULL)
    PK_EXPR_value_t *const_values;   --- constant values (NULL)
    };
typedef struct PK_EXPR_sf_s PK_EXPR_sf_t;




This structure contains an expression to be evaluated.


Specific Errors:
    PK_ERROR_bad_expr            A supplied root expression or sub-expression
                                 is invalid. (MILD)

    PK_ERROR_evaluator_failed    Failed to evaluate the expression, for example
                                 a function call within the expression failing
                                 to evaluate. (SERIOUS)

    PK_ERROR_bad_name            The expression contains a sub-expression or
                                 constant with a name that is not allowed.
                                 This includes having the same name as an input
                                 variable to the expression. (MILD)

    PK_ERROR_expr_dupl_defn      The expression contains duplicate names used
                                 for sub-expressions and/or constants. (MILD)

    PK_ERROR_expr_undef_symb     The root expression or sub-expressions contain
                                 undefined symbols. (MILD)

Used in:

PK_FACE_change_deform_o_t

The expressions language allows an application to supply a formula to evaluate,
in the form of one or more strings.

See here for more information.

Description of fields:

'root_expr'         The expression to evaluate.

'n_sub_exprs'       The number of sub-expressions.

'sub_expr_names'    An array of length 'n_sub_exprs', containing the name of
                    each sub-expression. Sub-expressions are optional, and
                    referenced by name by the root_expr. For example, if one
                    had a sub-expression named "sbx_my_sub_expr", then
                    referencing "sbx_my_sub_expr" in the 'root_expr' would
                    evaluate the expression definition corresponding to
                    "sbx_my_sub_expr".

'sub_expr_defs'     A parallel array containing the sub-expressions.

'n_consts'          The number of application constants. Constants are
                    optional, and if supplied may be referenced by expressions
                    (either the root expression, or sub-expressions).

'const_names'       An array of length 'n_consts', containing the name of each
                    constant.

'const_values'      A parallel array containing the value of each constant.