JackCompiler

JackCompiler extends JackAnalyzer (syntax analyzer) to form the frontend compiler to the VMtranslator backend compiler. The Jack compilation process consists of 2 stages:

1. programs written in the high level Jack language are first compiled down to a virtual machine (VM) language (similar to Java bytecode)
2. the VM compiler translates it down to the Hack assembly language

API

JackCompiler

Coordinates compiling a single file or directory. Functionality is almost identical to the JackAnalyzer module. A second command line arg can be passed which adds a postfix to the filename (useful for testing).

SymbolTable

Updates the symbol table whenever a class/subroutine variable declaration is found. This allows the compiler to map the variable names to the low level virtual memory segments that the Hack assembly language understands.

Method	Arguments	Return	function
constructor			init symbol table
startSubroutine			resets the subroutine level symbol table
define	name:string, type:string, kind: SymbolTableKinds {NONE, STATIC, FIELD, VAR, ARG}		Define a new symbol
varCount	kind: SymbolTableKinds	int	Returns the number of variables in the symbol table for that kind
kindOf	name: string	SymbolTableKinds	Returns the kind for a given variable name
typeOf	name: string	string	Returns the type for a given variable name
indexOf	name: string	int	Returns the index of the variable. This is used to map to a RAM address
exists	name: string	boolean	Returns true if the variable name exists in the table. Else false

VMWriter

Writes the VM commands to file

Method	Arguments	function
constructor	outputFilename	Creates a file outputFilename.vm for writing
writePush	segment:Segments {CONST, ARG, LOCAL, STATIC, THIS, THAT, POINTER, TEMP}, index:int	Write a push command to the virtual memory segment
writePop	segment:Segments {ARG, LOCAL, STATIC, THIS, THAT, POINTER, TEMP}, index:int	Write a pop command to the memory segment
writeArithmetic	command:Commands {ADD, SUB, NEG, AND, OR, NOT, EQ, GT, LT}	Write an logical or arithmetic command
writeLabel	label:string	Write a label command
writeGoto	label:string	Write a goto command
writeIf	label:string	Write an if-goto command
writeCall	name:string, nArgs:int	Write a function call command
writeFunction	name:string, nLocals:int	Write a function declaration command
writeReturn		Write a function return command

CompilationEngine

Compiles VM code. API is identical to the CompilationEngine module found in JackAnalyzer.

Install & Usage

npm install
node JackCompiler.js <src file/dir> [options]

Use --help flag for more options.

Testing

Each of the folders contains Jack programs used to test the compiler. All except ExpressionTest were provided by the nand2tetris course creators.

A bash script regressTest.sh compiles the Jack programs from custom test dirs I've written using this compiler as well as the course supplied JackCompiler and tests that they match. N.B. As development of the compiler continues, I've found the VM code my compiler generates deviates from the course provided one so its use is quite limited.