Yupana is a C library that evaluates arithmetic expression.
- single header/source file
- C99 standard compliant
- zero external dependencies
- thread safe
- create folder for a project and clone
yupanato it
mkdir app
cd app
git clone https://github.com/viktor-shepel/yupana.git- create
main.cfile with next content
#include <yupana.h>
#include <stdio.h>
int main() {
optional_number_t number = eval("1 + 2 / 5");
printf("eval(\"1 + 2 / 5\") == %g\n", number.value);
return 0;
}- compile project
gcc -Wall -std=c99 -c yupana/src/yupana.c -o yupana.o
gcc -Wall -std=c99 -I yupana/src/ -c main.c -o main.o
gcc main.o yupana.o -o main- run binary
./main
eval("1 + 2 / 5") == 1.4- have fun π
typedef struct {
const char* description;
const char* context;
} eval_error_t;Is a data structure that represents evaluation error. It maintains human readable description of error and place of it's origin as description/context fields respectively.
const char* expression = "2 / :five:";
eval_error_t error = eval(expression).error;
error.description; // points to string "division operator has malformed arguments"
error.context == &expression[4]; // true
/*
* Graphical interpretaton of error context
*
* eval_error_t erro = eval("2 / :five:").error;
* ^
* |
* error.context ---------------+
*/typedef struct {
bool valid;
double value;
eval_error_t error;
} optional_number_t;Is a data structure that represents evaluation that might fail.
Valid number represented as { .valid = true, .value = <actual value>, .erro = { NULL, NULL } }.
Invalid number represented as { .valid = false, .value = NaN, .error = <computation flaw> }.
optional_number_t number = eval("2 + (8 / 4)");
number.valid == true;
number.value == 4.0;
number.error.description == NULL;
number.error.context == NULL;
/* VS */
optional_number_t number = eval("2 + (8 / /)");
number.valid == false;
number.value == NAN; // don't compare in such way, it is implementation specific
number.error.description != NULL;
number.error.context != NULL;optional_number_t eval(const char* expression);Is a function that evaluates text with arithmetic expression expression. It returns optional number wich encapsulates double precision value for well formed expression or error for malformed one.
optional_number_t number = eval("0.1 + 0.2");
number.valid == true;
number.value == 0.3;
optional_number_t number = eval("NaN");
number.valid == true;
number.value == NAN; // if your platform supports NAN
optional_number_t number = eval("δΈ + δΈ");
number.valid == false;
number.value == NAN; // don't expect it to be 4.0
optional_number_t number = eval("I + III");
number.valid == false;
number.value == NAN; // same as above unless it runs on scholar pcnavigate to yupana folder and build examples (play with/explore it)
cd yupana
makerepl - for interactive exploration
calc - as pipe command
React
Typescript
Django
Laravel
Facebook
Microsoft
Google
Alibaba
D3
Tencent