A set of utilities for handling arithmetic expressions, converting them to RPN (Reverse Polish Notation), and evaluating them.

enum { STI_OP_ASSOC_LEFT = -1, STI_OP_ASSOC_NONE = 0, STI_OP_ASSOC_RIGHT = 1, STI_OP_OPEN_PAREN = 2, STI_OP_CLOSE_PAREN = 3, }; typedef struct sti_op_prec_rule { char* token; short prec; char assoc; char arity; } sti_op_prec_rule;

int infix_to_rpn(sti_op_prec_rule* rules, char** infix, char*** rpn, size_t* rpnlen)

Converts an infix-ordered list of tokens and converts it to a list of tokens in RPN order based on the rules provided. Internally uses the Shunting Yard algorithm.

Expression Parsing

int parse_arithmetic_string(char* src, char*** out, size_t* outlen)

Tokenizes a string containing arithmetic expressions in typical mathmatical (infix) notation and returns a list of duped strings for each token, trimmed of whitespace, in the order it appears in the input string.

Tokens are greedily interpreted as:

Operators: +, -, **, *, /, ~, &, |, ^, <<, >>
Grouping: (, ), [, ]
Numbers: [0-9.][0-9a-fA-F.]*

Evaluation

int64_t rpn_eval_int_str(char** rpn)

Evaluates a valid list of RPN tokens using signed 64-bit integers as the internal type. Numbers are parsed using strtol(str, NULL, 0).

Supported operators:

+ Addition.
- Subtraction.
* Multiplication.
/ Division.
% Integer Modulus.
** Exponentiation (implemented as naive looped multiplication).
& Bitwise AND.
| Bitwise OR.
^ Bitwise XOR.
~ Bitwise NOT.
<< Bit shift left.
>> Bit shift right.

double rpn_eval_double_str(char** rpn)

Evaluates a valid list of RPN tokens using signed 64-bit integers as the internal type. Numbers are parsed using strtod(str, NULL).

Supported operators:

+ Addition.
- Subtraction.
* Multiplication.
/ Division.
% Floating-point modulus.

RPN Utilities

Expression Parsing

Evaluation