Code Translation

Question 1

What is code translation?

Answer 1

In simple terms, it is the process of translating source code to object code.

Question 2

Special Programs for Translation

Answer 2

Four examples of programs used for translation include:
- Compiler
- Interpreter
- Assembler
- Linker

Question 3

Platform Independent

Answer 3

This means source code is portable, and writes the code as one simple text file. Then uses a compiler that targets a specific platform (source code and byte code).

Question 4

Platform Dependent

Answer 4

Compiler outputs assembly code or object code that will only run on the platform for which it was compiled (compile a game in c++, and run it on PC, Xbox etc). Examples include assembly code and machine code, or object code.

Question 5

Compiler v Interpreter

Answer 5

Compiler translates the whole code (returns a file of errors) and adds it to an executable, whilst interpreter runs line-by-line.
With compilers, translations and executions phases are separate, while for interpreters, they are interlaced.

Question 6

Compiler Advantages

Answer 6

Compilation process is faster than interpreter.
Compiled code runs much faster.
Checks for syntax AND semantic errors, but interpreters can only check for syntax errors.

Question 7

Interpreter Advantages

Answer 7

Syntax errors are easily identifiable.
Useful for rapid prototyping.
Debugging tools are easier to use.

Question 8

Java’s Exception with Compiler and Interpreter

Answer 8

Java uses best of both worlds, compiling the java with the java development kit (javac in terminal), and then running it with the interpreter, the java virtual machine (java in terminal).

Question 9

Interpreter Creation

Answer 9

At the origin of every interpreter there will be a compiler. Essentially, a compiled language will be needed to write the code for the interpreter.

Question 10

Single Pass Compiler

Answer 10

Moves through source code line-by-line and generates object code along the way.

Question 11

Multi-pass Compiler

Answer 11

Reads the entire source file into an internal data structure, and analyses and augments the data structure in multiple stages.

Question 12

Linking

Answer 12

There can be many source files, which compiled turns into object files, so it is the linker’s job to put all these together into one final executable program image.

Question 13

Static Linking

Answer 13

Static linking copies all the libraries used in our code into the final executable file.

Question 14

Dynamic Linking

Answer 14

Dynamic linking is the process of loading the external shared libraries into the program and then binds those shared libraries dynamically to the program.

Question 15

Lexical Component

Answer 15

List of all keywords allowed in language (import, public, else, while, for).

Question 16

Syntactical Component

Answer 16

Defines form and structure of legal expressions in the language (instead of saying private x double in Java, we would say private double x).

Question 17

Semantic Component

Answer 17

Adds meaning to an expression made from keywords (actions from an if-else statement etc).

Question 18

Grammar

Answer 18

Set of formal syntax rules.

Question 19

Tokens

Answer 19

Grouped characters from the translator.

Question 20

Expressions

Answer 20

One or more tokens.

Question 21

Non-terminal Expressions

Answer 21

Defined by other rules.

Question 22

Terminal Expressions

Answer 22

Defined in their final form with simple characters.

Question 23

Extended Backus-Naur Form

Answer 23

Rules that are defined as productions of non-terminal and terminal expressions.

Question 24

EBNF Matching

Answer 24

Allow the compiler to match the source code against the EBNF grammar of the language.

Question 25

EBNF Rules

Answer 25

-> defines a rule
“|” OR

<name> Non-terminal Symbol
symbol Terminal Symbol
[tokens] Optional Tokens
{tokens} Tokens repeated 0 or more times
* Tokens repeated zero or more times
\+ Tokens repeated one or more times
</name>