path: root/src/parser.c

#include "../include/parser.h"
#include "../include/ast.h"
#include "../include/compiler.h"
#include "../include/std/misc.h"
#include "../include/std/file.h"
#include "../include/std/mem.h"
#include "../include/std/log.h"
#include "../include/std/alloc.h"
#include "../include/std/hash.h"

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

#define throw(result) do { throw_debug_msg; longjmp(self->parse_env, (result)); } while(0)
#define throw_if_error(result) \
do { \
    int return_if_result; \
    return_if_result = (result); \
    if((return_if_result) != 0) \
        throw(return_if_result); \
} while(0)

#define VAR_MAX_LEN UINT8_MAX
#define FUNC_MAX_PARAMS 128
#define FUNC_MAX_RETURN_TYPES 128
#define FUNC_MAX_ARGS FUNC_MAX_PARAMS

static CHECK_RESULT Ast* parser_parse_rhs(Parser *self);
static CHECK_RESULT Ast* parser_parse_body(Parser *self);
static CHECK_RESULT StructField* parser_parse_struct_body(Parser *self);
static CHECK_RESULT Ast* parser_parse_rhs_binop(Parser *self);
static void parser_parse_var_type(Parser *self, VariableType *result);
static void parser_parse_var_type_def(Parser *self, VariableType *result);
static void parser_queue_file(Parser *self, BufferView path, ParserFileScopeReference **parser_file_scope);

int parser_init(Parser *self, amal_compiler *compiler, ArenaAllocator *allocator) {
    self->allocator = allocator;
    self->compiler = compiler;
    self->ssa = NULL;
    self->started = bool_false;
    self->error.index = 0;
    self->error.str = NULL;
    self->error_context = ERROR_CONTEXT_NONE;
    self->index = 0;
    return_if_error(structdecl_init(&self->struct_decl, &compiler->root_scope, allocator));
    lhsexpr_init(&self->file_decl, DECL_FLAG_EXTERN | DECL_FLAG_PUB | DECL_FLAG_CONST, create_buffer_view_null());
    return_if_error(ast_create(self->allocator, &self->struct_decl, AST_STRUCT_DECL, &self->file_decl.rhs_expr));
    return_if_error(buffer_init(&self->imports, allocator));
    return_if_error(hash_map_init(&self->imports_by_name, allocator, sizeof(usize), hash_map_compare_string, amal_hash_string));
    self->current_scope = &self->struct_decl.body;
    self->has_func_parent = bool_false;
    self->bytecode = NULL;
    return PARSER_OK;
}

static bool parser_is_current_scope_file_scope(Parser *self) {
    return self->current_scope == &self->struct_decl.body;
}

/*
BODY_LOOP = BODY* @end_token
*/
static void parser_parse_body_loop(Parser *self, Scope *scope, Token end_token) {
    int result;
    for(;;) {
        Ast *body_obj;
        bool is_end_token;
        throw_if_error(tokenizer_consume_if(&self->tokenizer, end_token, &is_end_token));
        if(is_end_token)
            break;
        
        body_obj = parser_parse_body(self);
        result = scope_add_child(scope, body_obj);
        if(result == 0) {
            continue;
        } else if(result == AST_ERR_DEF_DUP) {
            /* TODO: Convert ast type to string for error message */
            BufferView obj_name;
            obj_name = ast_get_name(body_obj);
            self->error = tokenizer_create_error(&self->tokenizer, 
                                                tokenizer_get_code_reference_index(&self->tokenizer, obj_name.data),
                                                "Variable with the name %.*s was declared twice in the same scope", obj_name.size, obj_name.data);
            self->error_context = ERROR_CONTEXT_NONE;
            throw(result);
        } else {
            throw(result);
        }
    }
}

/*
STRUCT_BODY_LOOP = '{' STRUCT_BODY* '}'
*/
static void parser_parse_struct_body_loop(Parser *self, StructDecl *struct_decl) {
    int result;
    throw_if_error(tokenizer_accept(&self->tokenizer, TOK_OPEN_BRACE));
    for(;;) {
        StructField *struct_field;
        bool is_end_token;
        throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_CLOSING_BRACE, &is_end_token));
        if(is_end_token)
            break;
        
        struct_field = parser_parse_struct_body(self);
        result = structdecl_add_field(struct_decl, struct_field, self->allocator);
        if(result == 0) {
            continue;
        } else if(result == AST_ERR_DEF_DUP) {
            self->error = tokenizer_create_error(&self->tokenizer,
                                                tokenizer_get_code_reference_index(&self->tokenizer, struct_field->name.data),
                                                "Variable with the name %.*s was declared twice in the struct", struct_field->name.size, struct_field->name.data);
            self->error_context = ERROR_CONTEXT_NONE;
            throw(result);
        } else {
            throw(result);
        }
    }
}

/*
FUNC_PARAM = TOK_IDENTIFIER VAR_TYPE_DEF
*/
static CHECK_RESULT bool parser_parse_function_parameter(Parser *self, FunctionParameter *result) {
    bool match;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_IDENTIFIER, &match));
    if(!match)
        return bool_false;

    result->name = self->tokenizer.value.identifier;
    parser_parse_var_type_def(self, &result->type);
    if(result->type.type == VARIABLE_TYPE_NONE) {
        self->error = tokenizer_create_error(&self->tokenizer,
                                             tokenizer_get_error_index(&self->tokenizer),
                                             "Expected ':' after parameter name");
        throw(PARSER_UNEXPECTED_TOKEN);
    }

    return bool_true;
}

/*
FUNC_PARAMS = FUNC_PARAM (',' FUNC_PARAM)*
*/
static void parser_parse_function_parameters(Parser *self, FunctionSignature *func_sig) {
    for(;;) {
        FunctionParameter func_param;
        bool match;
        int result;

        function_parameter_init(&func_param);
        if(!parser_parse_function_parameter(self, &func_param)) {
            self->error = tokenizer_create_error(&self->tokenizer,
                                                 tokenizer_get_error_index(&self->tokenizer),
                                                 "Expected closure parameter");
            throw(PARSER_UNEXPECTED_TOKEN);
        }

        result = function_signature_add_parameter(func_sig, &func_param);
        if(result == AST_ERR_DEF_DUP) {
            self->error = tokenizer_create_error(&self->tokenizer, 
                                                 tokenizer_get_code_reference_index(&self->tokenizer, func_param.name.data),
                                                 "Parameter with name %.*s was defined twice for the function", func_param.name.size, func_param.name.data);
            self->error_context = ERROR_CONTEXT_NONE;
            throw(result);
        } else if(result != 0) {
            throw(result);
        }
        throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_COMMA, &match));
        if(!match)
            return;
    }
}

/*
FUNC_RETURN_TYPES = VAR_TYPE (',' VAR_TYPE)*
*/
static void parser_parse_function_return_types(Parser *self, FunctionSignature *func_sig) {
    int return_type_index;
    return_type_index = 0;
    for(;;) {
        VariableType var_type;
        bool match;

        parser_parse_var_type(self, &var_type);
        if(var_type.type == VARIABLE_TYPE_NONE) {
            /* If function has no return types */
            if(return_type_index == 0)
                break;
            self->error = tokenizer_create_error(&self->tokenizer,
                                                 tokenizer_get_error_index(&self->tokenizer),
                                                 "Expected type or closure signature");
            throw(PARSER_UNEXPECTED_TOKEN);
        }
        throw_if_error(function_signature_add_return_type(func_sig, &var_type));
        throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_COMMA, &match));
        if(!match)
            break;
        ++return_type_index;
    }

    if (buffer_get_size(&func_sig->parameters, FunctionParameter) > FUNC_MAX_PARAMS) {
        self->error = tokenizer_create_error(&self->tokenizer,
                                             tokenizer_get_error_index(&self->tokenizer),
                                             "A closure can't have more than %d parameters", FUNC_MAX_PARAMS);
        throw(PARSER_ERR);
    }

    if (buffer_get_size(&func_sig->return_types, FunctionReturnType) > FUNC_MAX_RETURN_TYPES) {
        self->error = tokenizer_create_error(&self->tokenizer,
                                             tokenizer_get_error_index(&self->tokenizer),
                                             "A closure can't have more than %d return values", FUNC_MAX_RETURN_TYPES);
        throw(PARSER_ERR);
    }
}

/*
FUNC_SIGNATURE = 'fn' ('(' FUNC_PARAMS? ') FUNC_RETURN_TYPES? ')?
*/
static CHECK_RESULT FunctionSignature* parser_parse_function_signature(Parser *self) {
    FunctionSignature *signature;
    bool match;

    throw_if_error(arena_allocator_alloc(self->allocator, sizeof(FunctionSignature), (void**)&signature));
    throw_if_error(function_signature_init(signature, self->allocator));

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_FN, &match));
    if(!match)
        return NULL;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_OPEN_PAREN, &match));
    if(match) {
        bool has_closing_paren;
        throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_CLOSING_PAREN, &has_closing_paren));
        if(!has_closing_paren) {
            parser_parse_function_parameters(self, signature);
            throw_if_error(tokenizer_accept(&self->tokenizer, TOK_CLOSING_PAREN));
        }
        parser_parse_function_return_types(self, signature);
    }

    return signature;
}

/*
VAR_TYPE = TOK_IDENTIFIER|FUNC_SIGNATURE
*/
void parser_parse_var_type(Parser *self, VariableType *result) {
    bool match;

    result->type = VARIABLE_TYPE_NONE;
    result->value.variable = NULL;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_IDENTIFIER, &match));
    if(match) {
        result->type = VARIABLE_TYPE_VARIABLE;
        throw_if_error(arena_allocator_alloc(self->allocator, sizeof(Variable), (void**)&result->value.variable));
        variable_init(result->value.variable, self->tokenizer.value.identifier);
        return;
    }

    result->value.signature = parser_parse_function_signature(self);
    if(result->value.signature)
        result->type = VARIABLE_TYPE_SIGNATURE;
}

/*
VAR_TYPE_DEF = ':' VAR_TYPE
*/
void parser_parse_var_type_def(Parser *self, VariableType *result) {
    bool match;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_COLON, &match));
    if(!match) {
        result->type = VARIABLE_TYPE_NONE;
        result->value.variable = NULL;
        return;
    }

    parser_parse_var_type(self, result);
    if(result->type == VARIABLE_TYPE_NONE) {
        self->error = tokenizer_create_error(&self->tokenizer,
                                             tokenizer_get_error_index(&self->tokenizer),
                                             "Expected type or closure signature");
        throw(PARSER_UNEXPECTED_TOKEN);
    }
}

/*
LHS_DECLARATION = ('extern'|'export')? 'pub'? 'const'|'var' TOK_IDENTIFIER VAR_TYPE_DEF?
*/
static CHECK_RESULT LhsExpr* parser_parse_declaration_lhs(Parser *self) {
    LhsExpr *result;
    DeclFlag decl_flag;
    bool is_extern;
    bool is_export;
    bool is_pub;
    bool is_const;
    BufferView var_name;
    decl_flag = DECL_FLAG_NONE;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_EXTERN, &is_extern));
    if(is_extern) {
        decl_flag |= DECL_FLAG_EXTERN;
        if(self->has_func_parent) {
            self->error = tokenizer_create_error(&self->tokenizer,
                                                tokenizer_get_error_index(&self->tokenizer),
                                                "Only declarations in global structs can be extern");
            throw(PARSER_UNEXPECTED_TOKEN);
        }
    } else {
        throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_EXPORT, &is_export));
        if(is_export) {
            decl_flag |= DECL_FLAG_EXPORT;
            if(self->has_func_parent) {
                self->error = tokenizer_create_error(&self->tokenizer,
                                                    tokenizer_get_error_index(&self->tokenizer),
                                                    "Only declarations in global structs can be exported");
                throw(PARSER_UNEXPECTED_TOKEN);
            }
        }
    }

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_PUB, &is_pub));
    if(is_pub) {
        decl_flag |= DECL_FLAG_PUB;
        if(self->has_func_parent) {
            self->error = tokenizer_create_error(&self->tokenizer,
                                                tokenizer_get_error_index(&self->tokenizer),
                                                "Only declarations in global structs can be public");
            throw(PARSER_UNEXPECTED_TOKEN);
        }
    }

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_CONST, &is_const));
    if(is_const) {
        decl_flag |= DECL_FLAG_CONST;
    } else {
        bool isVar;

        if(is_extern || is_export) {
            self->error = tokenizer_create_error(&self->tokenizer,
                                                tokenizer_get_error_index(&self->tokenizer),
                                                "Extern and exported variables have to be declared with \"const\"");
            throw(PARSER_UNEXPECTED_TOKEN);
        }

        throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_VAR, &isVar));
        if(!isVar)
            return NULL;
    }

    throw_if_error(tokenizer_accept(&self->tokenizer, TOK_IDENTIFIER));
    var_name = self->tokenizer.value.identifier;
    throw_if_error(arena_allocator_alloc(self->allocator, sizeof(LhsExpr), (void**)&result));
    lhsexpr_init(result, decl_flag, var_name);

    if(var_name.size > VAR_MAX_LEN) {
        self->error = tokenizer_create_error(&self->tokenizer,
                                             tokenizer_get_code_reference_index(&self->tokenizer, var_name.data),
                                             "Variable name can't be longer than %d", VAR_MAX_LEN);
        throw(PARSER_ERR);
    }

    parser_parse_var_type_def(self, &result->type);
    return result;
}

/*

CLOSURE = FUNC_SIGNATURE '{' BODY_LOOP '}'
*/
static CHECK_RESULT FunctionDecl* parser_parse_closure(Parser *self) {
    FunctionSignature *signature;
    FunctionDecl *result;
    bool prev_has_func_parent;

    signature = parser_parse_function_signature(self);
    if(!signature)
        return NULL;

    /*
        TODO: Implement function declaration inside other functions.
        Such functions should be moved to the file scope in the bytecode generation
    */
    assert(parser_is_current_scope_file_scope(self) && "TODO: Implement function declaration inside other functions.");

    throw_if_error(arena_allocator_alloc(self->allocator, sizeof(FunctionDecl), (void**)&result));
    throw_if_error(funcdecl_init(result, signature, self->current_scope, self->allocator));
    signature->func_decl = result;
    result->body.function_signature = signature;

    self->current_scope = &result->body;
    prev_has_func_parent = self->has_func_parent;
    self->has_func_parent = bool_true;
    throw_if_error(tokenizer_accept(&self->tokenizer, TOK_OPEN_BRACE));
    parser_parse_body_loop(self, self->current_scope, TOK_CLOSING_BRACE);
    self->current_scope = result->body.parent;
    self->has_func_parent = prev_has_func_parent;
    return result;
}

/*
STRUCT = 'struct' '{' STRUCT_BODY_LOOP '}'
*/
static CHECK_RESULT StructDecl* parser_parse_struct_decl(Parser *self) {
    StructDecl *result;
    bool match;
    result = NULL;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_STRUCT, &match));
    if(!match)
        return result;

    throw_if_error(arena_allocator_alloc(self->allocator, sizeof(StructDecl), (void**)&result));
    throw_if_error(structdecl_init(result, self->current_scope, self->allocator));

    self->current_scope = &result->body;
    parser_parse_struct_body_loop(self, result);
    self->current_scope = result->body.parent;
    return result;
}

/*
FUNC_ARGS = (RHS_START)? (',' RHS_START)* ')'
*/
static void parser_parse_function_args(Parser *self, FunctionCall *func_call) {
    bool first_arg = bool_true;
    int arg_index = 0;

    for(;;) {
        Ast *arg_expr;
        bool is_end_token;

        throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_CLOSING_PAREN, &is_end_token));
        if(is_end_token)
            break;
        
        if(!first_arg)
            throw_if_error(tokenizer_accept(&self->tokenizer, TOK_COMMA));
        first_arg = bool_false;
        
        arg_expr = parser_parse_rhs(self);
        throw_if_error(buffer_append(&func_call->args, &arg_expr, sizeof(arg_expr)));
        ++arg_index;
        if (arg_index > FUNC_MAX_ARGS) {
            self->error = tokenizer_create_error(&self->tokenizer,
                                                 tokenizer_get_error_index(&self->tokenizer),
                                                 "A closure can't take more than %d arguments", FUNC_MAX_ARGS);
            throw(PARSER_ERR);
        }
    }
}

/*
VARIABLE = TOK_IDENTIFIER
FUNC_CALL_OR_VARIABLE = VARIABLE ('(' FUNC_ARGS ')')?
*/
static CHECK_RESULT Ast* parser_parse_function_call_or_variable(Parser *self) {
    Ast *result;
    bool match;
    BufferView identifier;
    FunctionCall *func_call;
    result = NULL;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_IDENTIFIER, &match));
    if(!match)
        return result;
    
    identifier = self->tokenizer.value.identifier;
    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_OPEN_PAREN, &match));
    if(!match) {
        Variable *variable;
        throw_if_error(arena_allocator_alloc(self->allocator, sizeof(Variable), (void**)&variable));
        variable_init(variable, identifier);
        throw_if_error(ast_create(self->allocator, variable, AST_VARIABLE, &result));
        return result;
    }
    
    throw_if_error(arena_allocator_alloc(self->allocator, sizeof(FunctionCall), (void**)&func_call));
    throw_if_error(funccall_init(func_call, self->tokenizer.value.identifier, self->allocator));
    throw_if_error(ast_create(self->allocator, func_call, AST_FUNCTION_CALL, &result));
    /* Ends after TOK_CLOSING_PAREN */
    parser_parse_function_args(self, func_call);
    return result;
}

/*
IMPORT = IMPORT_SYMBOL
*/
static CHECK_RESULT Import* parser_parse_import(Parser *self) {
    Import *result;
    bool match;
    result = NULL;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_IMPORT, &match));
    if(!match)
        return result;
    
    throw_if_error(arena_allocator_alloc(self->allocator, sizeof(Import), (void**)&result));
    import_init(result, self->tokenizer.value.string);
    return result;
}

/*
ELSE_IF_STATEMENT = 'else' ('if' RHS_BINOP)? ('{' BODY_LOOP '}')|BODY
*/
static CHECK_RESULT ElseIfStatement* parser_parse_else_if_statement(Parser *self) {
    ElseIfStatement *result;
    bool match;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_ELSE, &match));
    if(!match)
        return NULL;

    throw_if_error(arena_allocator_alloc(self->allocator, sizeof(ElseIfStatement), (void**)&result));
    throw_if_error(else_if_statement_init(result, self->current_scope, self->allocator));

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_IF, &match));
    if(match)
        result->condition = parser_parse_rhs_binop(self);

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_OPEN_BRACE, &match));
    if(match) {
        parser_parse_body_loop(self, &result->body, TOK_CLOSING_BRACE);
    } else {
        Ast *body_obj;
        body_obj = parser_parse_body(self);
        throw_if_error(scope_add_child(&result->body, body_obj));
    }

    return result;
}

static void parser_parse_else_if_statement_loop(Parser *self, IfStatement *if_stmt) {
    ElseIfStatement *else_if_stmt = NULL;
    for(;;) {
        ElseIfStatement *next_else_if;
        next_else_if = parser_parse_else_if_statement(self);
        if(!next_else_if)
            break;

        if(!else_if_stmt)
            if_stmt->else_if_stmt = next_else_if;
        else
            else_if_stmt->next_else_if_stmt = next_else_if;

        /* else statement that has no condition can't be followed by another else statement */
        if(!next_else_if->condition)
            break;
        else_if_stmt = next_else_if;
    }
}

/*
IF_STATEMENT = 'if' RHS_BINOP ('{' BODY_LOOP '}')|BODY ELSE_IF_STATEMENT*
*/
static CHECK_RESULT IfStatement* parser_parse_if_statement(Parser *self) {
    IfStatement *result;
    bool match;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_IF, &match));
    if(!match)
        return NULL;

    throw_if_error(arena_allocator_alloc(self->allocator, sizeof(IfStatement), (void**)&result));
    throw_if_error(if_statement_init(result, self->current_scope, self->allocator));

    result->condition = parser_parse_rhs_binop(self);

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_OPEN_BRACE, &match));
    if(match) {
        parser_parse_body_loop(self, &result->body, TOK_CLOSING_BRACE);
    } else {
        Ast *body_obj;
        body_obj = parser_parse_body(self);
        throw_if_error(scope_add_child(&result->body, body_obj));
    }

    parser_parse_else_if_statement_loop(self, result);
    return result;
}

/*
WHILE_STATEMENT = 'while' RHS_BINOP ('{' BODY_LOOP '}')|BODY
*/
static CHECK_RESULT WhileStatement* parser_parse_while_statement(Parser *self) {
    WhileStatement *result;
    bool match;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_WHILE, &match));
    if(!match)
        return NULL;

    throw_if_error(arena_allocator_alloc(self->allocator, sizeof(WhileStatement), (void**)&result));
    throw_if_error(while_statement_init(result, self->current_scope, self->allocator));

    result->condition = parser_parse_rhs_binop(self);

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_OPEN_BRACE, &match));
    if(match) {
        parser_parse_body_loop(self, &result->body, TOK_CLOSING_BRACE);
    } else {
        Ast *body_obj;
        body_obj = parser_parse_body(self);
        throw_if_error(scope_add_child(&result->body, body_obj));
    }

    return result;
}

static CHECK_RESULT Ast* parser_parse_number(Parser *self) {
    Ast *result;
    bool match;
    Number *number;
    result = NULL;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_NUMBER, &match));
    if(!match)
        return result;
    
    throw_if_error(arena_allocator_alloc(self->allocator, sizeof(Number), (void**)&number));
    number_init(number, self->tokenizer.value.integer, self->tokenizer.number_is_integer,
        create_buffer_view(self->tokenizer.code.data + self->tokenizer.prev_index, self->tokenizer.index - self->tokenizer.prev_index));
    throw_if_error(ast_create(self->allocator, number, AST_NUMBER, &result));
    return result;
}

/*
RHS_S = STRING | NUMBER | FUNC_CALL_OR_VARIABLE
*/
static CHECK_RESULT Ast* parser_parse_rhs_single_expr(Parser *self) {
    Ast *result;
    bool match;
    result = NULL;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_STRING, &match));
    if(match) {
        String *string;
        throw_if_error(arena_allocator_alloc(self->allocator, sizeof(String), (void**)&string));
        throw_if_error(string_init(string, self->tokenizer.value.string));
        throw_if_error(ast_create(self->allocator, string, AST_STRING, &result));
        return result;
    }

    result = parser_parse_number(self);
    if(result)
        return result;

    result = parser_parse_function_call_or_variable(self);
    if(result)
        return result;

    self->error = tokenizer_create_error(&self->tokenizer,
                                        tokenizer_get_error_index(&self->tokenizer),
                                        "Expected string, variable or function call");
    throw(PARSER_UNEXPECTED_TOKEN);
}

/*
RHS_BINOP_OPT_PAREN = RHS_S | '(' RHS_BINOP ')'
*/
static CHECK_RESULT Ast* parser_parse_rhs_binop_opt_paren(Parser *self) {
    Ast *result;
    bool match;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_OPEN_PAREN, &match));
    if(!match)
        return parser_parse_rhs_single_expr(self);

    result = parser_parse_rhs_binop(self);
    throw_if_error(tokenizer_accept(&self->tokenizer, TOK_CLOSING_PAREN));
    if(result->type == AST_BINOP)
        result->value.binop->grouped = bool_true;
    return result;
}

/*
RHS_BINOP = RHS_BINOP_OPT_PAREN (TOK_BINOP RHS_BINOP_OPT_PAREN)?

Note: Parantheses count has to match for the beginning paranthesis and the ending parenthesis.
*/
Ast* parser_parse_rhs_binop(Parser *self) {
    bool match;
    Ast *result;
    Ast *lhs;
    Ast *rhs;
    BinopType binop_type;
    Binop *binop;

    lhs = parser_parse_rhs_binop_opt_paren(self);
    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_BINOP, &match));
    if(!match)
        return lhs;
    binop_type = self->tokenizer.value.binop_type;

    rhs = parser_parse_rhs_binop(self);
    throw_if_error(arena_allocator_alloc(self->allocator, sizeof(Binop), (void**)&binop));
    binop_init(binop);
    binop->type = binop_type;
    binop->lhs = lhs;
    binop->rhs = rhs;
    throw_if_error(ast_create(self->allocator, binop, AST_BINOP, &result));
    return result;
}

/*
RHS = RHS_BINOP ';'

Note: Parantheses count has to match for the beginning paranthesis and the ending parenthesis.
*/
Ast* parser_parse_rhs(Parser *self) {
    /* TODO: If binop only contains one expression, then use that directly for @rhs_expr */
    Ast *result;
    result = parser_parse_rhs_binop(self);

    /* TODO: Implement this */
    /*binop_reorder_by_precedence(binop);*/
    return result;
}

static bool type_requires_semicolon_at_end(AstType type) {
    /* TODO: Check for tables */
    return type != AST_FUNCTION_DECL && type != AST_STRUCT_DECL && type != AST_IF_STATEMENT;
}

/*
BODY_SEMICOLON = ';'

Note: Semicolon is not required for closures, structs and tables
*/
static void parser_parse_body_semicolon(Parser *self, Ast *expr) {
    if(expr->type == AST_BINOP) {
        bool match;
        throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_SEMICOLON, &match));
        if(!match) {
            /* TODO: Specify all the binop characters instead of "binop" which doesn't make sense for the user */
            self->error = tokenizer_create_error(&self->tokenizer,
                                                tokenizer_get_error_index(&self->tokenizer),
                                                "Expected ';' or binop");
            throw(PARSER_UNEXPECTED_TOKEN);
        }
        return;
    }

    if(type_requires_semicolon_at_end(expr->type))
        throw_if_error(tokenizer_accept(&self->tokenizer, TOK_SEMICOLON));
}

/* CONDITIONAL = (IF_STATEMENT|WHILE_STATEMENT)? */
static CHECK_RESULT Ast* parser_parse_conditional(Parser *self) {
    Ast *result;
    IfStatement *if_stmt;
    WhileStatement *while_stmt;

    if_stmt = parser_parse_if_statement(self);
    if(if_stmt) {
        throw_if_error(ast_create(self->allocator, if_stmt, AST_IF_STATEMENT, &result));
        self->error_context = ERROR_CONTEXT_NONE;
        return result;
    }

    while_stmt = parser_parse_while_statement(self);
    if(while_stmt) {
        throw_if_error(ast_create(self->allocator, while_stmt, AST_WHILE_STATEMENT, &result));
        self->error_context = ERROR_CONTEXT_NONE;
        return result;
    }

    return NULL;
}

/*
LHS_RHS = CLOSURE|STRUCT|IMPORT
*/
static Ast* parser_parse_lhs_rhs(Parser *self, LhsExpr *lhs_expr) {
    Ast *result;
    FunctionDecl *func_decl;
    StructDecl *struct_decl;
    Import *import;

    func_decl = parser_parse_closure(self);
    if(func_decl) {
        if(buffer_get_size(&func_decl->signature->return_types, FunctionReturnType) > 1 && (LHS_EXPR_IS_EXTERN(lhs_expr) || LHS_EXPR_IS_EXPORT(lhs_expr))) {
            self->error = tokenizer_create_error(&self->tokenizer,
                                                 tokenizer_get_code_reference_index(&self->tokenizer, lhs_expr->var_name.data),
                                                 "Extern and export closures can only have one return value");
            throw(PARSER_ERR);
        }
        throw_if_error(ast_create(self->allocator, func_decl, AST_FUNCTION_DECL, &result));
        func_decl->lhs_expr = lhs_expr;
        return result;
    }
    
    struct_decl = parser_parse_struct_decl(self);
    if(struct_decl) {
        throw_if_error(ast_create(self->allocator, struct_decl, AST_STRUCT_DECL, &result));
        return result;
    }

    import = parser_parse_import(self);
    if(import) {
        parser_queue_file(self, import->path, &import->file_scope);
        throw_if_error(ast_create(self->allocator, import, AST_IMPORT, &result));
        parser_parse_body_semicolon(self, result);
        return result;
    }

    return NULL;
}

/*
RETURN = 'return' RHS
*/
static ReturnExpr* parser_parse_return(Parser *self) {
    bool match;
    ReturnExpr *result;

    throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_RETURN, &match));
    if(!match)
        return NULL;

    throw_if_error(arena_allocator_alloc(self->allocator, sizeof(ReturnExpr), (void**)&result));
    return_expr_init(result, parser_parse_rhs(self));
    return result;
}

/*
BODY =  (LHS_DECLARATION ';') |
        (LHS_DECLARATION '=' LHS_RHS|(RHS BODY_SEMICOLON)) |
        CONDITIONAL |
        (RHS ';'|('=' RHS BODY_SEMICOLON))
*/
Ast* parser_parse_body(Parser *self) {
    Ast *result;
    LhsExpr *lhs_expr;
    ReturnExpr *return_expr;
    Ast *rhs_expr;

    lhs_expr = parser_parse_declaration_lhs(self);
    if(lhs_expr) {
        bool match;

        throw_if_error(ast_create(self->allocator, lhs_expr, AST_LHS, &result));
        if(LHS_EXPR_IS_EXTERN(lhs_expr)) {
            throw_if_error(tokenizer_accept(&self->tokenizer, TOK_SEMICOLON));
            if (lhs_expr->type.type == VARIABLE_TYPE_NONE) {
                self->error = tokenizer_create_error(&self->tokenizer, tokenizer_get_code_reference_index(&self->tokenizer, lhs_expr->var_name.data), "An extern variable can't be declared without a type");
                throw(PARSER_UNEXPECTED_TOKEN);
            }
            return result;
        } else {
            throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_SEMICOLON, &match));
            if(match) {
                if(lhs_expr->type.type == VARIABLE_TYPE_SIGNATURE) {
                    self->error = tokenizer_create_error(&self->tokenizer, tokenizer_get_code_reference_index(&self->tokenizer, lhs_expr->var_name.data), "Expected function declaration. Only extern functions can have empty declarations.");
                    throw(PARSER_UNEXPECTED_TOKEN);
                } else if (lhs_expr->type.type == VARIABLE_TYPE_NONE) {
                    /* TODO: Allow this for non-const variables */
                    self->error = tokenizer_create_error(&self->tokenizer, tokenizer_get_code_reference_index(&self->tokenizer, lhs_expr->var_name.data), "A variable can't be declared without a type or assignment");
                    throw(PARSER_UNEXPECTED_TOKEN);
                } else if(LHS_EXPR_IS_CONST(lhs_expr)) {
                    self->error = tokenizer_create_error(&self->tokenizer, tokenizer_get_code_reference_index(&self->tokenizer, lhs_expr->var_name.data), "A const variable can't be declared without assignment");
                    throw(PARSER_UNEXPECTED_TOKEN);
                }
                return result;
            }
        }

        throw_if_error(tokenizer_accept(&self->tokenizer, TOK_EQUALS));

        lhs_expr->rhs_expr = parser_parse_lhs_rhs(self, lhs_expr);
        if(lhs_expr->rhs_expr)
            return result;
    } else {
        self->error_context = ERROR_CONTEXT_NO_LHS;
        result = parser_parse_conditional(self);
        if(result)
            return result;
    }

    if(self->has_func_parent) {
        return_expr = parser_parse_return(self);
        if(return_expr) {
            throw_if_error(tokenizer_accept(&self->tokenizer, TOK_SEMICOLON));
            throw_if_error(ast_create(self->allocator, return_expr, AST_RETURN, &result));
            return result;
        }
    }

    self->error_context = ERROR_CONTEXT_RHS_STANDALONE;
    rhs_expr = parser_parse_rhs(self);
    self->error_context = ERROR_CONTEXT_NONE;
    /* Variable declaration with lhs and rhs */
    if(lhs_expr) {
        lhs_expr->rhs_expr = rhs_expr;
    } else {
        bool match;
        throw_if_error(tokenizer_consume_if(&self->tokenizer, TOK_EQUALS, &match));
        /* Variable assignment */
        if(match) {
            AssignmentExpr *assign_expr;
            throw_if_error(arena_allocator_alloc(self->allocator, sizeof(AssignmentExpr), (void**)&assign_expr));
            throw_if_error(ast_create(self->allocator, assign_expr, AST_ASSIGN, &result));
            assign_expr->lhs_expr = rhs_expr;

            self->error_context = ERROR_CONTEXT_RHS_STANDALONE;
            assign_expr->rhs_expr = parser_parse_rhs(self);
            self->error_context = ERROR_CONTEXT_NONE;
        } else {
            /* Only rhs (for example function call, binop etc...) */
            result = rhs_expr;
        }
    }

    parser_parse_body_semicolon(self, rhs_expr);
    return result;
}

/*
STRUCT_BODY = TOK_IDENTIFIER VAR_TYPE_DEF ';'
*/
StructField* parser_parse_struct_body(Parser *self) {
    BufferView var_name;
    VariableType var_type;
    StructField *struct_field;

    throw_if_error(tokenizer_accept(&self->tokenizer, TOK_IDENTIFIER));
    var_name = self->tokenizer.value.identifier;
    parser_parse_var_type_def(self, &var_type);
    if(var_type.type == VARIABLE_TYPE_NONE) {
        self->error = tokenizer_create_error(&self->tokenizer,
                                             tokenizer_get_error_index(&self->tokenizer),
                                             "Expected ':' after struct field name");
        throw(PARSER_UNEXPECTED_TOKEN);
    }
    throw_if_error(tokenizer_accept(&self->tokenizer, TOK_SEMICOLON));
    throw_if_error(arena_allocator_alloc(self->allocator, sizeof(StructField), (void**)&struct_field));
    structfield_init(struct_field, var_name, &var_type);
    return struct_field;
}

/*
ROOT = BODY_LOOP
*/
int parser_parse_buffer(Parser *self, BufferView code_buffer, BufferView buffer_name) {
    int result;
    self->file_decl.var_name = buffer_name;
    throw_if_error(tokenizer_init(&self->tokenizer, self->allocator, code_buffer, buffer_name, &self->compiler->options));
    result = setjmp(self->parse_env);
    if(result == 0)
        parser_parse_body_loop(self, &self->struct_decl.body, TOK_END_OF_FILE);
    else if(self->error.str != NULL) {
        switch(self->error_context) {
            case ERROR_CONTEXT_NONE:
                tokenizer_print_error_object(&self->tokenizer, &self->error);
                break;
            case ERROR_CONTEXT_RHS_STANDALONE:
                /* TODO: Only show "return" in error message if @self->has_func_parent */
                tokenizer_print_error(&self->tokenizer, self->tokenizer.prev_index, "Expected string, variable, closure, struct, function call, import or return");
                break;
            case ERROR_CONTEXT_NO_LHS:
                tokenizer_print_error(&self->tokenizer, self->tokenizer.prev_index, "Expected variable declaration, string, variable or function call");
                break;
            default:
                assert(bool_false && "Error context handling not implemented");
                break;
        }
    }
    if(result != 0)
        amal_log_error("Failed, reason: %d", result);
    return result;
}

int parser_parse_file(Parser *self, BufferView filepath) {
    Buffer file_content;
    return_if_error(buffer_init(&file_content, self->allocator));
    assert(!self->started && "Parser can't be reused. Create a new parser.");
    self->started = bool_true;
    assert(filepath.size > 0 && filepath.data[filepath.size] == '\0');
    return_if_error(read_whole_file(filepath.data, &file_content));
    return parser_parse_buffer(self, create_buffer_view(file_content.data, file_content.size), filepath);
}

static CHECK_RESULT int file_path_join(BufferView directory, BufferView file, char **result_path) {
    /*                                        '/'             '\0'                    */
    return_if_error(am_malloc(directory.size + 1 + file.size + 1, (void**)result_path));
    am_memcpy(*result_path, directory.data, directory.size);
    (*result_path)[directory.size] = '/';
    am_memcpy(*result_path + directory.size + 1, file.data, file.size);
    (*result_path)[directory.size + 1 + file.size] = '\0';
    return 0;
}

/*
Path can be path to included library path (or system library path) in which case
the path separator is a dot, otherwise the path separator is forward slash '/'
*/
void parser_queue_file(Parser *self, BufferView path, ParserFileScopeReference **parser_file_scope) {
    /* TODO: Parse special path (to include library path with dots) */
    FileScopeReference *file_scope;
    BufferView file_directory;
    char *path_relative;
    int result;

    file_directory = file_get_parent_directory(self->tokenizer.code_name);
    throw_if_error(file_path_join(file_directory, path, &path_relative));
    /* We want buffer to be null-terminated but null character should not be included for the size */
    result = amal_compiler_internal_load_file(self->compiler, path_relative, &file_scope);
    if(result != 0) {
        self->error = tokenizer_create_error(&self->tokenizer, 
                                             tokenizer_get_code_reference_index(&self->tokenizer, path.data),
                                             "Failed to while parsing path %s (invalid path?)", path_relative);
        am_free(path_relative);
        throw(result);
    }
    am_free(path_relative);

    {
        usize parser_file_scope_index;
        int num_imports;
        BufferView import_path_canonical = create_buffer_view(file_scope->canonical_path.data, file_scope->canonical_path.size);

        if(hash_map_get(&self->imports_by_name, import_path_canonical, &parser_file_scope_index)) {
            *parser_file_scope = buffer_get(&self->imports, parser_file_scope_index, sizeof(ParserFileScopeReference*));
            return;
        }

        num_imports = buffer_get_size(&self->imports, ParserFileScopeReference*);
        if(num_imports == 254) {
            self->error = tokenizer_create_error(&self->tokenizer, 
                                                 tokenizer_get_error_index(&self->tokenizer),
                                                 "One file can't have more than 255 imports");
            throw(PARSER_ERR);
        }

        throw_if_error(arena_allocator_alloc(self->allocator, sizeof(ParserFileScopeReference*), (void**)parser_file_scope));
        (*parser_file_scope)->file_scope_ref = file_scope;
        (*parser_file_scope)->import_index = num_imports;
        throw_if_error(buffer_append(&self->imports, parser_file_scope, sizeof(ParserFileScopeReference*)));
        throw_if_error(hash_map_insert(&self->imports_by_name, import_path_canonical, &parser_file_scope_index));
    }
}