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/**
* mds — A micro-display server
* Copyright © 2014, 2015, 2016, 2017 Mattias Andrée (maandree@kth.se)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef MDS_MDS_KBDC_VARIABLES_H
#define MDS_MDS_KBDC_VARIABLES_H
#include "tree.h"
#include "string.h"
/**
* Destroy the variable storage
*/
void variables_terminate(void);
/**
* Push the variable-stack, making it
* possible to shadow all variables
*
* @return Zero on success, -1 on error
*/
void variables_stack_push(void);
/**
* Undo the actions of `variables_stack_push`
* and all additions to the variable storage
* since it was last called (without a
* corresponding call to this function)
*/
void variables_stack_pop(void);
/**
* Check whether a let will override a variable
* rather the define or shadow it
*
* @param variable The variable index
* @return Whether a let will override the variable
*/
__attribute__((pure))
int variables_let_will_override(size_t variable);
/**
* Assign a value to a variable, and define or shadow it in the process
*
* @param variable The variable index
* @param value The variable's new value
* @return Zero on success, -1 on error
*/
int variables_let(size_t variable, mds_kbdc_tree_t *restrict value);
/**
* Get the value currently assigned to a variable
*
* The function cannot fail, `NULL` is however returned
* if the variable is not defined
*
* @param variable The variable index
* @return The variable's value, `NULL` if not defined
*/
__attribute__((pure))
mds_kbdc_tree_t *variables_get(size_t variable);
/**
* Mark a variable as having been unsed in a for-loop in the current scope
*
* @param variable The variable index, must already be defined
* @return Zero on success, -1 on error
*/
int variables_was_used_in_for(size_t variable);
/**
* Check whether a variable has been used in a for-loop in the current scope
*
* @param variable The variable index, must already be defined
* @return Whether `variables_was_used_in_for` has been unused on the variable
*/
__attribute__((pure))
int variables_has_been_used_in_for(size_t variable);
#endif
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