feat: finished the new firsts system and began supporting redirections

src/parser/grammar.c

@@ -13,30 +13,13 @@ static struct firsts_list *firsts_map = NULL;
 
 // === Static functions
 
-/* @brief get the first accepted tokens of a rule
- *
- * @arg r the rule
- * @return the accepted tokens as a firsts_list struct
- */
-static struct firsts_list *first(enum rule r)
-{
-    if (firsts_map == NULL || firsts_map[r].tokens == NULL)
-    {
-        puts("Internal error: attempted to get the firsts of a rule without "
-             "properly initializing the firsts map");
-        return NULL;
-    }
-
-    return &firsts_map[r];
-}
-
 /* @brief Add a token to a rule's firsts (in firsts_map)
  *
  * @arg rule the rule to which add a first
  * @arg token the token to add to the rule's firsts
  * @return true on success, false on error
  */
-static bool add_first(enum rule rule, struct token token)
+static bool add_first(enum rule rule, enum token_type token)
 {
     struct firsts_list *item = &firsts_map[rule];
     if (item->tokens != NULL)
@@ -44,20 +27,20 @@ static bool add_first(enum rule rule, struct token token)
         // Check for duplicates
         for (size_t i = 0; i < item->list_length; i++)
         {
-            if (item->tokens[i].type == token.type)
+            if (item->tokens[i] == token)
                 return true;
         }
 
         // Append
         item->list_length++;
         item->tokens = realloc(
-            item->tokens, (item->list_length) * sizeof(struct firsts_list));
+            item->tokens, (item->list_length) * sizeof(enum token_type));
     }
     else
     {
         // Create entry
-        item->tokens =
-            calloc(item->list_length + 1, sizeof(struct firsts_list));
+        item->list_length = 1;
+        item->tokens = calloc(1, sizeof(enum token_type));
     }
 
     // Check for alloc error
@@ -100,7 +83,45 @@ bool grammar_init(void)
         return false;
 
     // Populate the firsts map
-    // TODO
+    add_first(RULE_INPUT, TOKEN_WORD);
+    add_first(RULE_INPUT, TOKEN_IF);
+    add_first(RULE_INPUT, TOKEN_NEWLINE);
+    add_first(RULE_INPUT, TOKEN_EOF);
+
+    add_first(RULE_LIST, TOKEN_WORD);
+    add_first(RULE_LIST, TOKEN_IF);
+
+    add_first(RULE_AND_OR, TOKEN_WORD);
+    add_first(RULE_AND_OR, TOKEN_IF);
+
+    add_first(RULE_PIPELINE, TOKEN_WORD);
+    add_first(RULE_PIPELINE, TOKEN_IF);
+
+    add_first(RULE_COMMAND, TOKEN_WORD);
+    add_first(RULE_COMMAND, TOKEN_IF);
+
+    add_first(RULE_SIMPLE_COMMAND, TOKEN_WORD);
+
+    add_first(RULE_SHELL_COMMAND, TOKEN_IF);
+
+    add_first(RULE_IF, TOKEN_IF);
+
+    add_first(RULE_COMPOUND_LIST, TOKEN_NEWLINE);
+    add_first(RULE_COMPOUND_LIST, TOKEN_WORD);
+    add_first(RULE_COMPOUND_LIST, TOKEN_IF);
+
+    add_first(RULE_ELSE_CLAUSE, TOKEN_ELSE);
+    add_first(RULE_ELSE_CLAUSE, TOKEN_ELIF);
+
+    add_first(RULE_ELEMENT, TOKEN_WORD);
+    add_first(RULE_ELEMENT, TOKEN_IONUMBER);
+    add_first(RULE_ELEMENT, TOKEN_REDIRECTION);
+
+    add_first(RULE_REDIRECTION, TOKEN_IONUMBER);
+    add_first(RULE_REDIRECTION, TOKEN_REDIRECTION);
+
+    add_first(RULE_PREFIX, TOKEN_IONUMBER);
+    add_first(RULE_PREFIX, TOKEN_REDIRECTION);
 
     return true;
 }
@@ -119,6 +140,30 @@ void grammar_close(void)
     firsts_map = NULL;
 }
 
+struct firsts_list *first(enum rule rule)
+{
+    if (firsts_map == NULL || firsts_map[rule].tokens == NULL)
+    {
+        puts("Internal error: attempted to get the firsts of a rule without "
+             "properly initializing the firsts map");
+        return NULL;
+    }
+
+    return &firsts_map[rule];
+}
+
+bool is_first(struct token token, enum rule rule)
+{
+    struct firsts_list *firsts = &firsts_map[rule];
+    for (size_t i = 0; i < firsts->list_length; i++)
+    {
+        if (firsts->tokens[i] == token.type)
+            return true;
+    }
+
+    return false;
+}
+
 struct ast *parse_input(struct lexer_context *ctx)
 {
     return parse_list(ctx);

src/parser/grammar.h

@@ -37,27 +37,49 @@ enum rule {
     RULE_IF,
     RULE_COMPOUND_LIST,
     RULE_ELSE_CLAUSE,
+    RULE_ELEMENT,
+    RULE_REDIRECTION,
+    RULE_PREFIX,
     NUMBER_OF_RULES
 };
 
 struct firsts_list {
-    struct token* tokens; // Heap allocated array
+    enum token_type* tokens; // Heap allocated array
     size_t list_length;
 };
 
 // === Functions
 
-/* @brief Initializes the grammar submodule
+/*
+ * @brief Initializes the grammar submodule
  * @return PARSER_INIT_SUCCESS on success PARSER_INIT_ERROR on error
  * @warning Do not use outside the parser
  */
 bool grammar_init(void);
 
-/* @brief Closes the grammar submodule
+/*
+ * @brief Closes the grammar submodule
  * @warning Do not use outside the parser
  */
 void grammar_close(void);
 
+/*
+ * @brief get the first accepted tokens of a rule
+ *
+ * @arg r the rule
+ * @return the accepted tokens as a firsts_list struct
+ */
+struct firsts_list *first(enum rule r);
+
+/*
+ * @brief tells is token belong to the firsts of a specific rule
+ *
+ * @arg token
+ * @arg rule
+ * @return true if token belongs to rule's firsts, false otherwise
+ */
+bool is_first(struct token token, enum rule rule);
+
 /* @brief Acts as the entry point of the parser, calls parse_list
  *
  * @code input = list '\n'

src/parser/grammar_advanced.c

@@ -1,6 +1,8 @@
 #include "grammar_advanced.h"
 
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
 #include "grammar_basic.h"
 
@@ -10,6 +12,12 @@ struct ast *parse_redirection(struct lexer_context *ctx)
     if (token->type == TOKEN_IONUMBER)
     {
         // TODO
+    }
+    
+    int io_number = -1;
+    if (token->type == TOKEN_IONUMBER)
+    {
+        io_number = atoi(token->data);
         POP_TOKEN();
         token = PEEK_TOKEN();
     }
@@ -20,6 +28,20 @@ struct ast *parse_redirection(struct lexer_context *ctx)
              "else");
         return NULL;
     }
+    char *redir_op = strdup(token->data);
+    POP_TOKEN();
+
+    token = PEEK_TOKEN();
+    if (token->type != TOKEN_WORD)
+    {
+        puts("Syntax error: expected a word after redirection");
+        free(redir_op);
+        return NULL;
+    }
+    char *target = strdup(token->data);
+    POP_TOKEN();
+
+    return ast_create_redir(io_number, redir_op, target);
 }
 
 struct ast *parse_prefix(struct lexer_context *ctx)

src/parser/grammar_basic.c

@@ -43,15 +43,15 @@ struct ast *parse_list(struct lexer_context *ctx)
     while (token->type == TOKEN_SEMICOLON)
     {
         token = POP_TOKEN();
-        current_node = parse_and_or(ctx);
-        if (current_node == NULL)
-        {
-            // TODO free list
-            // There must be a function for that
-            return NULL;
-        }
-        result_list = list_append(result_list, current_node);
         token = PEEK_TOKEN();
+        if (is_first(*token, RULE_AND_OR))
+        {
+            current_node = parse_and_or(ctx);
+            if (current_node == NULL)
+                return NULL;
+            result_list = list_append(result_list, current_node);
+            token = PEEK_TOKEN();
+        }
     }
 
     return ast_create_list(result_list);
@@ -138,7 +138,7 @@ struct ast *parse_simple_command(struct lexer_context *ctx)
     token = PEEK_TOKEN();
 
     // Eventual elements
-    while (token->type == TOKEN_WORD)
+    while (is_first(*token, RULE_ELEMENT))
     {
         // Get element
         struct ast *element = parse_element(ctx);
@@ -170,7 +170,6 @@ struct ast *parse_simple_command(struct lexer_context *ctx)
         }
 
         // Forward
-        POP_TOKEN();
         token = PEEK_TOKEN();
     }
 
@@ -189,9 +188,8 @@ struct ast *parse_element(struct lexer_context *ctx)
     struct token *token = PEEK_TOKEN();
     if (token->type == TOKEN_WORD)
     {
-        // TODO
-        puts("NOT IMPLEMENTED");
-        return NULL;
+        token = POP_TOKEN();
+        return ast_create_word(token->data);
     }
     else if (token->type == TOKEN_IONUMBER || token->type == TOKEN_REDIRECTION)
     {
@@ -310,11 +308,14 @@ struct ast *parse_compound_list(struct lexer_context *ctx)
         }
 
         // And/or
-        current_cmd = parse_and_or(ctx);
-        if (current_cmd == NULL)
-            return NULL;
-        result_list = list_append(result_list, current_cmd);
-
+        if (is_first(*token, RULE_AND_OR))
+        {
+            current_cmd = parse_and_or(ctx);
+            if (current_cmd == NULL)
+                return NULL;
+            result_list = list_append(result_list, current_cmd);
+        }
+        
         token = PEEK_TOKEN();
     }