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/*
exprDefs.h
Private defs used by Expression and the parsing modules.
*/
#import "Expression.h"
/* a type of function term we know how to parse */
typedef struct _Function {
char *name;
int minArgs;
int maxArgs;
EXPTermEvalFunc *evalFunc;
} Function;
typedef enum { /* various types of terms we know about */
constantTerm = 1,
varTerm = 2,
vectorTerm = 4,
binOpTerm = 8,
funcTerm = 16
} TermTag;
/* a term of an expression.
Note that even if a constant is an integer, we store it as a float. This
ensures that divide by zero results in NaN ("not a number", a special
floating point value) instead of a coredump due to an arithmetic exception.
*/
typedef struct _EXPTerm {
TermTag tag; /* type of term */
union {
struct {
BOOL isInt; /* is this an integer? */
float val; /* the constant value */
} constant;
struct {
char *name; /* name of var */
float val; /* value of var */
} var;
struct {
BOOL hasRange; /* do we calc the vector or the range? */
BOOL changed; /* do we need to recalc? */
short dimension; /* dimension within which we vary */
char *name; /* name of var */
int resolution; /* last resolution we calc'ed at */
float min; /* range of values */
float max;
float *vals; /* list of values */
} vector;
struct {
char op; /* char representing op (e.g. '+', '-',...) */
} binOp;
struct {
Function *type; /* info for this type of function */
} func;
} data;
int numSubterms; /* number of subTerms from parse */
struct _EXPTerm *subterms[1]; /* the subTerms */
} Term;
typedef struct _TermList { /* a list of terms */
int num;
Term *terms[1];
} TermList;
/* declaration of functions shared between the parsing modules */
extern Term *_EXPAllocTerm(NXZone *zone, TermTag tag, int numSubterms, ...);
extern void _EXPFreeTerm(void *info, Term *data);
extern BOOL _EXPParseExpression(const char *text, NXHashTable *validTerms, Term **parseTree, NXHashTable *varTerms, NXZone *zone);
extern void _EXPPrepareToScan(const char *text);
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.