LexMath: A lexer/tokenizer for mathematical expressions

Installation

• Go to the latest release
• Download the RPM file for Red-Hat based Linux Systems, DEB file for Debian based systems, the DLL or LIB file for Windows, or the PKG file for MacOS

# Ubuntu/Debian
sudo dpkg -i <file>.deb

# RedHat Based Linux
sudo rpm -i <file>.rpm

# MacOS
installer -pkg <file>.pkg -target /

For Windows, you have to link it into the Visual Studio Project using the Linker menu in the Properties of the Project. Then download the lexmath.h file and include that as a header file.

Usage

#include <lexmath.h>

const char* lexList[9] = {
    "LEX_ADD", // + token
    "LEX_DIV", // / token
    "LEX_MUL", // * token
    "LEX_BRAC_START", // ( token
    "LEX_BRAC_END", // ) token
    "LEX_EXP", // ^ token
    "LEX_SUB", // - token
    "LEX_NAME", // list of characters from a-z
    "LEX_NUM" // A number (floating point included)
};

int main() {
    struct LexList* list = lex("1+sin(2x) * 1+3+3^3"); // List of tokens
    struct LexToken* lst = list->data; // The pointer to the tokens
    for (size_t i = 0; i < list->length; i++){ // Iterate over the tokens
        printf("Type: %s (%d)\n", lexList[lst[i].type], lst[i].type); // Print the Type
        if (lst[i].data){ // If there is data to print
            printf("Value: %s\n", lst[i].data); // Print the data
        }
        printf("\n"); // Print a new line
    }
    free_lex(list); // Free the tokens
    
}

OUTPUT

Type: LEX_NUM (8)
Value: 1

Type: LEX_ADD (0)

Type: LEX_NAME (7)
Value: sin

Type: LEX_BRAC_START (3)

Type: LEX_NUM (8)
Value: 2

Type: LEX_NAME (7)
Value: x

Type: LEX_BRAC_END (4)

Type: LEX_MUL (2)

Type: LEX_NUM (8)
Value: 1

Type: LEX_ADD (0)

Type: LEX_NUM (8)
Value: 3

Type: LEX_ADD (0)

Type: LEX_NUM (8)
Value: 3

Type: LEX_EXP (5)

Type: LEX_NUM (8)
Value: 3

Credits

• avighnac who introduced the idea of making a mathematical expression parser.