Compiler for language for Turing machine simulator.

The syntax of the language:

<program> := <symbol list> <main-statement>

<main-statement> := <statement>

<statement> := <block-statement> | <if-statement> | <if_else-statement> | <while-statement> | <do_while-statement>| <repeat_until-statement> | <write-statement> | <left-statement> | <right-statement> | <exit-statement> | <error-statement> | <continue-statement> | <break-statement> | <switch-statement>

<block-statement> := '{' <statement>+ '}'

<if-statement> := 'if' <symbol list> <statement>

<if_else-statement> := 'if' <symbol list> <statement> 'else' <statement>

<while-statement> := 'while' <symbol list> <statement>

<do_whlie-statement> := 'do' <statement> 'while' <symbol list> ';'

<repeat_until-statement> := 'repeat' <statement> 'until' <symbol list> ';'

<write-statement> := 'write' <symbol> ';'

<left-statement> := 'left' ';'

<right-statement> := 'right' ';'

<exit-statement> := 'exit' ';'

<error-statement> := 'error' ';'

<continue-statement> := 'cointinue' ';'

<break-statement> := 'break' ';'

<switch-statement> ::= 'switch' '()' <case-statements>

<case-statements> ::= <case-statement>+

<case-statement> := 'case' '(' <symbol> ')' <statement>

<symbol list> := <not> '(' <symbol> ( <comma> <symbol> )* ')' | '(' <symbol> ( <comma> <symbol> )* ')'

<symbol> = ASCII printable character

<not> := 'not'

<comma> := ','

Description of statements.

• if statement
  The statements of if statement are executed only if the symbol in the current cell of the tape is available in symbol list.

• if-else statement
  The if branch statements of if-else statement are executed when the symbol in the current cell of the tape is available in symbol list, otherwhies the else branch statements are exequted.

• while statement
  The statements of while statement are executed while the symbol in the current cell of the tape is available in symbol list.

• do_while statement
  The statements of do_while statement are executed while the symbol in the current cell of the tape is available in symbol list. In contrast of while statement, the statements are eqequted at least once.

• repeat_until statement
  The statements of repeat_until statement are executed until the symbol in the current cell of the tape is available in symbol list.

• switch statement
  Similar of common languages (C, C++, etc.) switch-case statement.

• write statement
  Writes the symbol in the currect cell of the tape.

• left statement
  Turns the head of the machine left.

• right statement
  Turns the head of the machine left.

• exit statement
  Halts the machine.

• error statement
  Gives error command to the machine to halt unsuccessfully.

• continue/break statements
  These statements are used as flow controls in while, do_while and repeat_until loops.
  If these statements aren't contained in any of loops given above, the parser trows an exception.

The compiler pareses program using tree based algorithm.