Making: math interpreter. Need to fix printf %f

src/kernel/kmain.c

@@ -39,7 +39,6 @@ int kmain(int retvalue)
   
   timer_install();
   keyboard_install();
-
   shell_install();
 
   return retvalue;

src/kernel/shell.c

@@ -21,7 +21,7 @@ void shell_install()
     }
     else if (strcmp(input_buffer, "help") == 0)
     {
-        printf("help\tpanic\twords\tprimes\trainbow\tclear\n");
+        printf("help\tpanic\twords\tprimes\trainbow\tclear\nmath\n");
     }
     else if (strcmp(input_buffer, "panic") == 0)
     {
@@ -43,6 +43,10 @@ void shell_install()
     {
 	program_clear();
     }
+    else if (strcmp(input_buffer, "math") == 0)
+    {
+	    program_math();
+    }
     else {
 	printf("Unknown command %s\n", input_buffer);
     }

src/libc/ctype.c

@@ -0,0 +1,13 @@
+
+#include "stdint.h"
+
+bool isdigit(char c)
+{
+	return c >= '0' && c <= '9';
+}
+
+
+bool isspace(char c)
+{
+	return c == ' ' || c == '\t' || c == '\n' || c == '\v' || c == '\f' || c == '\r';
+}

src/libc/ctype.h

@@ -0,0 +1,9 @@
+#ifndef CTYPE_H
+#define CTYPE_H
+
+#include "stdint.h"
+
+bool isdigit(char c);
+bool isspace(char c);
+
+#endif

src/libc/stdio.c

@@ -176,6 +176,50 @@ void colorputs(const char* str, unsigned int color)
   }
 }
 
+// double to string for printf
+void dtostrf(double val, char *buffer, int precision)
+{
+  int whole_part = (int)val;
+  double fractional_part = val - whole_part;
+  if (fractional_part < 0) fractional_part = -fractional_part;
+
+  char *start = buffer;
+  if (whole_part == 0)
+  {
+    *buffer++ = '0';
+  }
+  else
+  {
+    if (whole_part < 0)
+    {
+      *buffer++ = '-';
+      whole_part = -whole_part;
+    }
+    char temp[32];
+    int pos = 0;
+
+    while (whole_part > 0)
+    {
+      temp[pos++] = '0' + (whole_part % 10);
+      whole_part /= 10;
+    }
+    while (pos > 0)
+    {
+      *buffer++ = temp[--pos];
+    }
+  }
+
+  *buffer++ = '.';
+  for (int i = 0; i < precision; i++)
+  {
+    fractional_part *= 10;
+    int digit = (int)fractional_part;
+    *buffer++ = '0' + digit;
+    fractional_part -= digit;
+  }
+  *buffer = '\0';
+}
+
 void printf(const char* fmt, ...)
 {
   int* argp = (int*) &fmt;
@@ -270,6 +314,16 @@ void printf(const char* fmt, ...)
             sign = false;
             argp = printf_number(argp, length, sign, radix);
             break;
+          case 'f': {
+            // Handle floating-point numbers
+            double* dargp = (double*)argp;
+            double d = *(double*)dargp;
+            char buffer[64];
+            dtostrf(d, buffer, 6); // Default precision: 6
+            puts(buffer);
+            argp += 2; // Incrementing by 2 to move past the double argument
+            break;
+          }
           default:
             break;
         }

src/programs/math.c

@@ -0,0 +1,260 @@
+// Math expression lexer and parser
+
+#include "../libc/stdint.h"
+#include "../kernel/system.h"
+#include "../libc/stdio.h"
+#include "../libc/ctype.h"
+
+#define BUFFER_SIZE 256
+
+typedef enum
+{
+	TOKEN_NUMBER,
+	TOKEN_PLUS,
+	TOKEN_MINUS,
+	TOKEN_MULTIPLY,
+	TOKEN_DIVIDE,
+	TOKEN_LPAREN,
+	TOKEN_RPAREN,
+	TOKEN_END
+} TokenType;
+
+typedef struct
+{
+	TokenType type;
+	double value;
+} Token;
+
+typedef struct
+{
+	const char *text;
+	size_t pos;
+	Token current_token;
+} Lexer;
+
+void lexer_init(Lexer *lexer, const char *text)
+{
+	lexer->text = text;
+	lexer->pos = 0;
+	lexer->current_token.type = TOKEN_END;
+	lexer->current_token.value = 0;
+}
+
+void lexer_advance(Lexer *lexer)
+{
+	lexer->pos++;
+}
+
+char lexer_peek(const Lexer *lexer)
+{
+	return lexer->text[lexer->pos];
+}
+
+bool lexer_is_at_end(const Lexer *lexer)
+{
+	return lexer->text[lexer->pos] == '\0';
+}
+
+Token lexer_get_next_token(Lexer *lexer)
+{
+	while (!lexer_is_at_end(lexer))
+	{
+		char current_char = lexer_peek(lexer);
+
+		if (isspace(current_char)) {
+			lexer_advance(lexer);
+			continue;
+		}
+
+		if (isdigit(current_char)) {
+			double value = 0;
+			while (isdigit(current_char))
+			{
+				value = value * 10 + (current_char - '0');
+				lexer_advance(lexer);
+				current_char = lexer_peek(lexer);
+			}
+				if (current_char == '.')
+				{
+					lexer_advance(lexer);
+					double decimal_place = 0.1;
+					while (isdigit(lexer_peek(lexer))) 
+					{
+						value += decimal_place * (lexer_peek(lexer)-'0');
+						decimal_place *= 0.1;
+						lexer_advance(lexer);
+					}
+				}
+				lexer->current_token.type = TOKEN_NUMBER;
+				lexer->current_token.value = value;
+				//printf("NUMBER %f\n", value);
+				return lexer->current_token;
+		}
+
+		if (current_char == '+')
+		{
+			lexer_advance(lexer);
+			lexer->current_token.type = TOKEN_PLUS;
+			printf("PLUS\n");
+			return lexer->current_token;
+		}
+
+		if (current_char == '-') 
+		{
+			lexer_advance(lexer);
+			lexer->current_token.type = TOKEN_MINUS;
+			printf("MINUS\n");
+			return lexer->current_token;
+		}
+
+		if (current_char == '*')
+		{
+			lexer_advance(lexer);
+			lexer->current_token.type = TOKEN_MULTIPLY;
+			printf("MULTIPLY\n");
+			return lexer->current_token;
+		}
+
+		if (current_char == '/')
+		{
+			lexer_advance(lexer);
+			lexer->current_token.type = TOKEN_DIVIDE;
+			printf("DIVIDE\n");
+			return lexer->current_token;
+		}
+
+		if (current_char == '(')
+		{
+			lexer_advance(lexer);
+			lexer->current_token.type = TOKEN_LPAREN;
+			printf("LPAREN\n");
+			return lexer->current_token;
+		}
+
+		if (current_char == ')')
+		{
+			lexer_advance(lexer);
+			lexer->current_token.type = TOKEN_RPAREN;
+			printf("RPAREN\n");
+			return lexer->current_token;
+		}
+
+		printf("Unknown character %c\n", current_char);
+		//shell_install();
+	}
+	
+	lexer->current_token.type = TOKEN_END;
+	printf("END\n");
+	return lexer->current_token;
+}
+
+typedef struct
+{
+	Lexer lexer;
+	Token current_token;
+} Parser;
+
+void parser_init(Parser *parser, const char *text)
+{
+	lexer_init(&parser->lexer, text);
+	parser->current_token = lexer_get_next_token(&parser->lexer);
+}
+
+void parser_eat(Parser *parser, TokenType type)
+{
+	if (parser->current_token.type == type)
+	{
+		parser->current_token = lexer_get_next_token(&parser->lexer);
+	} else {
+		printf("Unexpected token %d\n", parser->current_token.type);
+		//shell_install();
+	}
+}
+
+double parser_factor(Parser *parser);
+double parser_term(Parser *parser);
+double parser_expression(Parser *parser);
+
+double parser_factor(Parser *parser)
+{
+	Token token = parser->current_token;
+	if (token.type == TOKEN_NUMBER)
+	{
+		parser_eat(parser, TOKEN_NUMBER);
+		//printf("Factor: %f\n", token.value);
+		return token.value;
+	} else if (token.type == TOKEN_LPAREN) {
+		parser_eat(parser, TOKEN_LPAREN);
+		double result = parser_expression(parser);
+		parser_eat(parser, TOKEN_RPAREN);
+		//printf("Factor (expression): %f\n", result);
+		return result;
+	} else {
+		printf("Unexpected token in factor %d\n", token.type);
+		//shell_install();
+	}
+	return -1;
+}
+
+double parser_term(Parser *parser)
+{
+	double result = parser_factor(parser);
+	//printf("Initial term: %f\n", result);
+
+	while (parser->current_token.type == TOKEN_MULTIPLY || parser->current_token.type == TOKEN_DIVIDE)
+	{
+		Token token = parser->current_token;
+		if (token.type == TOKEN_MULTIPLY) 
+		{
+			parser_eat(parser, TOKEN_MULTIPLY);
+			result *= parser_factor(parser);
+			//printf("Term after multiply: %f\n", result);
+		} else if (token.type == TOKEN_DIVIDE) {
+			parser_eat(parser, TOKEN_DIVIDE);
+			result /= parser_factor(parser);
+			//printf("Term after divide: %f\n", result);
+		}
+	}
+	return result;
+}
+
+double parser_expression(Parser *parser)
+{
+	double result = parser_term(parser);
+	//printf("Initial expression: %f\n", result);
+
+	while (parser->current_token.type == TOKEN_PLUS || parser->current_token.type == TOKEN_MINUS) 
+	{
+		Token token = parser->current_token;
+		if (token.type == TOKEN_PLUS)
+		{
+			parser_eat(parser, TOKEN_PLUS);
+			result += parser_term(parser);
+			//printf("Expression after plus: %f\n", result);
+		} else if (token.type == TOKEN_MINUS) {
+			parser_eat(parser, TOKEN_MINUS);
+			result -= parser_term(parser);
+			//printf("Expression after minus: %f\n", result);
+		}
+	}
+	return result;
+}
+
+double parse(const char* text)
+{
+	Parser parser;
+	parser_init(&parser, text);
+	double result = parser_expression(&parser);
+	//printf("Final result: %f\n", result);
+	return result;
+}
+
+void program_math()
+{
+	char input_buffer[BUFFER_SIZE];
+	puts("Expression? ");
+	get_input(input_buffer, BUFFER_SIZE);
+	printf("Input: %s\n", input_buffer);
+	double result = parse(input_buffer);
+	printf("\n%f\n", result);
+}

src/programs/programs.h

@@ -3,6 +3,7 @@
 
 void program_words();
 void program_primes();
+void program_math();
 
 // Misc
 void program_rainbow();