bsu_st_interpreter

BSU Capstone senior project - Structured Text Interpreter

Dev Environment Setup

From inside st_interpret directory:

Install cargo-c into cargo for automatic C header file and build management:

$ cargo install cargo-c

It then can be built by calling:

$ cargo cbuild

Tests can be run by calling:

$ cargo ctest

Ref: https://crates.io/crates/cargo-c

Built Library Location

After calling cargo cbuild, the library file can be found in the target folder.

Rust API

st_program_load(filename: &str) -> InterpreterResult

Load a Structured Text program from a file.

Arguments: filename - the name of the file to load

st_program_step(program_handle: &mut ProgHandle) -> InterpreterResult

Step forward one line in the program.

Arguments: program_handle

st_program_run(program_handle: &mut ProgHandle) -> InterpreterResult<()>

Run the whole program

Arguments: program_handle

get_all_vars(program_handle: &ProgHandle) -> Iter<'_, String, VariableInfo>

Retrieve all the currently in scope variables and return an iterator.

Arguments: program_handle

get_var(program_handle: &ProgHandle, name: String) -> Option<&VariableInfo>

Retrieve a variable with the given name.

Arguments: program_handle, name - the name of the variable to retrieve

update_var(program_handle: &mut ProgHandle, name: &str, new_value: VariableValue) -> InterpreterResult<()>

Change the value of a variable.

Arguments: program_handle, name - the name of the variable to update, new_value - the new value for the variable

add_var(program_handle: &mut ProgHandle, name: String, kind: VariableKind, value: VariableValue) -> InterpreterResult<()>

Add a new variable.

Arguments: program_handle, name - the name of the variable to add, Kind - the kind of variable, Value - the value for the variable

C API

st_program_load(filename: *const c_char) -> ProgHandlePointer

Loads a ST program from a file and returns a pointer to a program handle

Arguments: filename - the name of the file to load

st_program_step(program_handle: &mut ProgHandlePointer) -> bool

Executes one line of a program then returns true if the program has finished execution and false otherwise.

Arguments: program_handle - a pointer to a program handle that was generated by st_program_load

st_program_run(program_handle: &mut ProgHandlePointer)

Runs an entire ST program.

Arguments: program_handle - a pointer to a program handle that was generated by st_program_load

get_all_vars(program_handle: &ProgHandlePointer) -> Option<Box>

Returns a linked list of all the currently in scope variables.

Arguments: program_handle - a pointer to a program handle that was generated by st_program_load

get_var(program_handle: &ProgHandlePointer, name: *mut c_char) -> Option<Box> Looks for a variable with the given name, and returns it if found. Arguments: program_handle - a pointer to a program handle that was generated by st_program_load name - the name of the variable

update_var(program_handle: &mut ProgHandlePointer, name: *const c_char, value_type: *const c_char, value: *const c_char)

Updates a variable with a new value.

Arguments: program_handle - a pointer to a program handle that was generated by st_program_load, name - the name of the variable, value_type - the type of the variable, value - the new value for the variable

add_var(program_handle: &mut ProgHandlePointer, name: *const c_char, kind: *const c_char, value_type: *const c_char, value: *const c_char)

Adds a new variable with the given value.

Arguments: program_handle - a pointer to a program handle that was generated by st_program_load, name - the name of the variable, kind - the kind of variable, value_type - the type of the variable, value - the new value for the variable

destroy_variable_name_info(var_name_info: Box)

Passes the strings in the VariableNameInfo struct back to Rust code so that the memory can be managed. This needs to be called in order to avoid a memory leak. The strings should not be freed in the C code. More information can be found here: https://doc.rust-lang.org/std/ffi/struct.CString.html#method.from_raw.

Arguments: var_name_info - the struct to destroy