WIP

.gitignore

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+target/

makefile

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+TARGET := ./target
+SRC := ./src
+CC := clang -c -std=c17 -Wall -Wextra -pedantic -Werror 
+
+SRCS := $(shell find $(SRC) -name '*.c')
+OBJS := $(SRCS:%=$(TARGET)/%.o)
+
+#$(TARGET)/lox: $(OBJS)
+#	clang $(TARGET)/lox.o -L$(TARGET) -ltokens.o -o $(TARGET)/lox
+
+
+$(TARGET)/%.c.o: $(SRC)/%.c $(TARGET)
+	$(CC) $< -o $@
+
+$(TARGET):
+	mkdir -p $(TARGET)
+	
+clean:
+	rm -r $(TARGET)/*
+

src/lox.c

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+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
+#include "tokens.h"
+
+int run_file(char* file);
+void run_prompt(void);
+void run(char* source);
+void scan_tokens(char* source);
+void scan_token(char* source, int line, int start, int* current_pos, TokenList* token_list);
+void error(int line, char* nessage);
+void report(int line, char* where, char* message);
+char* substring(char* string, int position, int length);
+
+static bool had_error = false;
+
+int main(int argc, char* argv[]){
+    if (argc>2){
+        puts("Usage: lox [script]");
+        return EXIT_FAILURE;
+    } else if (argc == 2){
+        return run_file(argv[1]);
+    } else {
+        run_prompt();
+    }
+    return EXIT_SUCCESS;
+}
+
+
+int run_file(char* filename){
+    FILE* file = fopen(filename, "r");
+    if (file == NULL){
+        printf("unable to open file '%s'\n", filename);
+        return EXIT_FAILURE;
+    }
+    char line[255];
+    
+    char* content = malloc(1);
+    if (content == NULL){
+        puts("Out of memory");
+        return EXIT_FAILURE;
+    }
+    content[0] = '\0';
+    
+        
+    while (fgets(line, sizeof(line), file)){
+        content = realloc(content, strlen(content) + strlen(line) + 1 );
+        if (content == NULL){
+            return EXIT_FAILURE;
+        }
+        strcat(content, line);
+    }        
+    
+    fclose(file);
+   
+    run(content);
+
+    // FREE UP
+    free(content);
+    
+    if (had_error){
+        return 65;
+    }
+
+    return EXIT_SUCCESS;
+}
+
+void run_prompt(void){
+    char line[255];
+
+    for (;;){
+        printf(">");
+        char* r = fgets(line, 255, stdin);
+        
+        if (r == NULL){
+            break;
+        } 
+
+        run(line);
+        had_error = false;
+    }
+}
+
+void run(char* source){
+    printf("%s", source);
+    scan_tokens(source);
+}
+
+void scan_tokens(char* source){
+    int current = 0;
+    int start = 0;
+    int line = 1;
+
+    TokenList token_list;
+    tokenlist_init(&token_list);
+
+    while (current < (int)strlen(source)) {
+        start = current;
+        scan_token(source, line, start, &current, &token_list);
+    }
+    tokenlist_print(&token_list);
+}
+
+void add_token(char* source, int line, TokenList* token_list, enum TokenType type, int start, int current_pos){
+    Token token;
+    token.type = type;
+    token.lexeme = substring(source, start, current_pos);
+    token.literal = NULL;
+    token.line = line;
+       
+    tokenlist_add(token_list, token);
+}
+
+void scan_token(char* source, int line, int start, int* current_pos, TokenList* token_list){
+    char c = source[*current_pos];
+    (*current_pos) += 1;
+    switch (c){
+        case '(': add_token(source, line, token_list, LEFT_PAREN, start, *current_pos); break;
+        case ')': add_token(source, line, token_list, RIGHT_PAREN, start, *current_pos); break;
+        case '{': add_token(source, line, token_list, LEFT_BRACE, start, *current_pos); break;
+        case '}': add_token(source, line, token_list, RIGHT_BRACE, start, *current_pos); break;
+        case ',': add_token(source, line, token_list, COMMA, start, *current_pos); break;
+        case '.': add_token(source, line, token_list, DOT, start, *current_pos); break;
+        case '+': add_token(source, line, token_list, PLUS, start, *current_pos); break;
+        case ';': add_token(source, line, token_list, SEMICOLON, start, *current_pos); break;
+        case '/': add_token(source, line, token_list, SLASH, start, *current_pos); break;
+    }
+}
+
+void error(int line, char* message){
+    report(line, "", message);
+}
+
+void report(int line, char* where, char* message){
+    printf("[Line %i] Error %s : %s\n", line, where, message);
+    had_error = true;
+}
+
+char* substring(char* string, int position, int length){
+    char* ptr = malloc(length+1);
+    if (ptr == NULL) {
+        printf("out of memory");
+        exit(EXIT_FAILURE);
+    }
+
+    int c;
+    for (c=0; c< length; c++){
+        *(ptr+c) = *(string+position-1);
+        string += sizeof(char);
+    }
+    *(ptr+c) = '\0';
+
+    return ptr;
+}
+    

src/tokens.c

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+#include <stdlib.h>
+#include <stdio.h>
+#include "tokens.h"
+
+char* token_name(Token* token){
+    char* type;
+    switch (token->type){
+        case LEFT_PAREN: type = "LEFT_PAREN"; break;
+        case RIGHT_PAREN: type = "RIGHT_PAREN"; break;
+        case LEFT_BRACE: type = "LEFT_BRACE"; break;
+        case RIGHT_BRACE: type = "RIGHT_BRACE"; break;
+        case COMMA: type = "COMMA"; break;
+        case DOT: type = "DOT"; break;
+        case MINUS: type = "MINUS"; break;
+        case PLUS: type = "PLUS"; break;
+        case SEMICOLON: type = "SEMICOLON"; break;
+        case SLASH: type = "SLASH"; break;
+        case STAR: type = "STAR"; break;
+        case BANG: type = "BANG"; break;
+        case BANG_EQUAL: type = "BANG_EQUAL"; break;
+        case EQUAL: type = "EQUAL"; break;
+        case EQUAL_EQUAL: type = "EQUAL_EQUAL"; break;
+        case GREATER: type = "GREATER"; break;
+        case GREATER_EQUAL: type = "GREATER_EQUAL"; break;
+        case LESS: type = "LESS"; break;
+        case LESS_EQUAL: type = "LESS_EQUAL"; break;
+        case IDENTIFIER: type = "IDENTIFIER"; break;
+        case STRING: type = "STRING"; break;
+        case NUMBER: type = "NUMBER"; break;
+        case AND: type = "AND"; break;
+        case CLASS: type = "CLASS"; break;
+        case ELSE: type = "ELSE"; break;
+        case FALSE: type = "FALSE"; break;
+        case FUN: type = "FUN"; break;
+        case FOR: type = "FOR"; break;
+        case IF: type = "IF"; break;
+        case NIL: type = "NIL"; break;
+        case OR: type = "OR"; break;
+        case PRINT: type = "PRINT"; break;
+        case RETURN: type = "RETURN"; break;
+        case SUPER: type = "SUPER"; break;
+        case THIS: type = "THIS"; break;
+        case TRUE: type = "TRUE"; break;
+        case VAR: type = "VAR"; break;
+        case WHILE: type = "WHILE"; break;
+        case END_OF_FILE: type = "EOF"; break;
+    }
+    return type;
+}
+
+void tokenlist_init(TokenList* list){
+    list->tokens = malloc(sizeof(Token) * 32);
+    list->size = 0;
+    list->capacity = 32;
+}
+
+void tokenlist_add(TokenList* list, Token value){
+    if (list->size >= list->capacity){
+        list->capacity *= 2;
+        list->tokens = realloc(list->tokens, sizeof(Token)* list->capacity);
+    }
+    list->tokens[list->size] = value;
+    list->size +=1;
+}
+
+Token* tokenlist_get(TokenList* list, int index){
+    if (index >= list->size || index < 0){
+        printf("Index %d out of bounds for list of size %d\n", index, list->size);
+        exit(1);
+    }
+    return &list->tokens[index];
+}
+
+void tokenlist_print(TokenList* tokenlist){
+    for (int i=0; i< tokenlist->size; i++){
+        printf("%s, ", token_name(tokenlist_get(tokenlist, i)));
+    }
+}
+
+void tokenlist_free(TokenList* list){
+    free(list->tokens);
+}
+

src/tokens.h

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+#ifndef TOKENS_H
+#define TOKENS_H
+
+enum TokenType{
+    LEFT_PAREN, RIGHT_PAREN, LEFT_BRACE, RIGHT_BRACE, 
+    COMMA, DOT, MINUS, PLUS, SEMICOLON, SLASH, STAR,
+    BANG, BANG_EQUAL, EQUAL, EQUAL_EQUAL,
+    GREATER, GREATER_EQUAL, LESS, LESS_EQUAL,
+    IDENTIFIER, STRING, NUMBER,
+    AND, CLASS, ELSE, FALSE, FUN, FOR, IF, NIL, OR,
+    PRINT, RETURN, SUPER, THIS, TRUE, VAR, WHILE,
+    END_OF_FILE
+};
+
+typedef struct {
+    enum TokenType type;
+    char* lexeme;
+    void* literal;
+    int line;
+} Token;
+
+char* token_name(Token* token);
+
+typedef struct {
+    Token* tokens;
+    int size;
+    int capacity;
+} TokenList;
+
+void tokenlist_init(TokenList* list);
+
+void tokenlist_add(TokenList* list, Token value);
+
+Token* tokenlist_get(TokenList* list, int index);
+
+void tokenlist_print(TokenList* tokenlist);
+
+void tokenlist_free(TokenList* list);
+
+#endif