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Refactored so that functions can be declared before the statements th…
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…at comprise them. Manually tested that var declaration counting is working
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Isaiah Becker-Mayer committed Apr 7, 2021
1 parent 570f5f2 commit 6792483
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Showing 11 changed files with 4,097 additions and 69 deletions.
104 changes: 35 additions & 69 deletions Compiler/pkg/compiler/compilationengine.go
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Original file line number Diff line number Diff line change
@@ -1,13 +1,11 @@
package compiler

import (
"encoding/xml"
"errors"
"fmt"
"log"
"os"
"runtime"
"strconv"
)

//SyntaxError logs the function name, file, and line number
Expand All @@ -29,7 +27,6 @@ type CompilationEngine struct {
jackFilePath string // The name of the .jack input file to be compiled.
jt *JackTokenizer // A tokenizer set up to tokenize the file we want to compile
outputFile *os.File // The output file
xmlEnc *xml.Encoder // The xml encoder for testing
st *SymbolTable // The symbol table
className string // The class name being compiled. Set at compileClass
}
Expand All @@ -50,16 +47,12 @@ func NewCompilationEngine(jackFilePath string) (*CompilationEngine, error) {
ce.jt = jt

// Create the output file
outputFile, err := os.Create(fmt.Sprintf("%v_out.xml", ce.jackFilePath[0:len(ce.jackFilePath)-len(".jack")]))
outputFile, err := os.Create(fmt.Sprintf("%v.vm", ce.jackFilePath[0:len(ce.jackFilePath)-len(".jack")]))
if err != nil {
return nil, err
}
ce.outputFile = outputFile

// Create xml encoder
ce.xmlEnc = xml.NewEncoder(outputFile)
ce.xmlEnc.Indent("", " ")

// Create the symbol table
st := NewSymbolTable()
ce.st = st
Expand All @@ -70,7 +63,6 @@ func NewCompilationEngine(jackFilePath string) (*CompilationEngine, error) {
// Run runs the compiler on ce.jackFilePath
func (ce *CompilationEngine) Run() error {
defer ce.outputFile.Close()
defer ce.xmlEnc.Flush()

// Advance to eat the first token and call compileClass, which will recursively compile the entire file
if err := ce.advance(); err != nil {
Expand All @@ -79,26 +71,6 @@ func (ce *CompilationEngine) Run() error {
return ce.compileClass()
}

// Shorthand for opening an xml tag
func (ce *CompilationEngine) openXMLTag(tag string) error {
return ce.xmlEnc.EncodeToken(xml.StartElement{Name: xml.Name{Space: "", Local: tag}, Attr: []xml.Attr{}})
}

// Shorthand for writing raw data in an XML tag, prefixed and postfixed with a space character
func (ce *CompilationEngine) writeXMLData(data string) error {
return ce.xmlEnc.EncodeToken(xml.CharData(fmt.Sprintf(" %v ", data)))
}

// Shorthand for closing an xml tag
func (ce *CompilationEngine) closeXMLTag(tag string) error {
return ce.xmlEnc.EncodeToken(xml.EndElement{Name: xml.Name{Space: "", Local: tag}})
}

// Shorthand for calling jt.MarshalXML to take advantage of already existing xml encoding logic
func (ce *CompilationEngine) marshaljt() error {
return ce.jt.MarshalXML(ce.xmlEnc, xml.StartElement{Name: xml.Name{Space: "not used", Local: "not used"}, Attr: []xml.Attr{}})
}

// advance throws an error if there are no more tokens, else it returns ce.jt.Advance()
func (ce *CompilationEngine) advance() error {
if !ce.jt.HasMoreTokens() {
Expand Down Expand Up @@ -273,14 +245,17 @@ func (ce *CompilationEngine) compileSubroutine() error {
// Clear the subroutine table
ce.st.StartSubroutine()

// Confirm that current token is "constructor" or "function" or "method"
// Calling function checked that current token is "constructor" or "function" or "method"
if kw, err := ce.jt.KeyWord(); !(kw == "constructor" || kw == "function" || kw == "method") {
if err != nil {
return SyntaxError(err)
}
return SyntaxError(fmt.Errorf("expected %v \"constructor\" or \"function\" or \"method\"", keyWord))
}

// begin to declare the function
ce.outputFile.WriteString(fmt.Sprintf("function %v.", ce.className))

if err := ce.advance(); err != nil {
return err
}
Expand All @@ -295,10 +270,11 @@ func (ce *CompilationEngine) compileSubroutine() error {
if err := ce.advance(); err != nil {
return err
}
_, err = ce.jt.Identifier()
subroutineName, err := ce.jt.Identifier()
if err != nil {
return SyntaxError(err)
}
ce.outputFile.WriteString(fmt.Sprintf("%v ", subroutineName))

// Eat the subroutineName
if err := ce.advance(); err != nil {
Expand All @@ -309,16 +285,7 @@ func (ce *CompilationEngine) compileSubroutine() error {
return SyntaxError(err)
}

if err := ce.compileSubroutineBody(); err != nil {
return SyntaxError(err)
}

return nil
}

// '{' varDec* statements '}'
func (ce *CompilationEngine) compileSubroutineBody() error {
var err error
// subroutineBody: '{' varDec* statements '}'

// Eat what should be a "{"
if err = ce.advance(); err != nil {
Expand All @@ -327,23 +294,20 @@ func (ce *CompilationEngine) compileSubroutineBody() error {
if err = ce.checkForSymbol("{"); err != nil {
return SyntaxError(err)
}

// Eat the "{"
if err = ce.advance(); err != nil {
return SyntaxError(err)
}

// varDec*
for kw, _ := ce.jt.KeyWord(); kw == "var"; kw, _ = ce.jt.KeyWord() {
if err = ce.compileVarDec(); err != nil {
return SyntaxError(err)
}
// compiled a varDec, advance and try again or move on
if err = ce.advance(); err != nil {
return SyntaxError(err)
}
if err := ce.compileVarDecs(); err != nil {
return SyntaxError(err)
}

// now that all the vars have been declared, we know how to declare the vm code function
ce.outputFile.WriteString(fmt.Sprintf("%v\n", ce.st.VarCount(KIND_VAR)))

// statements
if err = ce.compileStatements(); err != nil {
return SyntaxError(err)
}
Expand All @@ -355,6 +319,24 @@ func (ce *CompilationEngine) compileSubroutineBody() error {
return nil
}

// varDec*
// compileVarDecs compiles all the variable declarations, so that when it returns a call to
// ce.st.VarCount(KIND_VAR) will give you the number of local variables for the current subroutine
func (ce *CompilationEngine) compileVarDecs() error {
var err error
// varDec*
for kw, _ := ce.jt.KeyWord(); kw == "var"; kw, _ = ce.jt.KeyWord() {
if err = ce.compileVarDec(); err != nil {
return SyntaxError(err)
}
// compiled a varDec, advance and try again or move on
if err = ce.advance(); err != nil {
return SyntaxError(err)
}
}
return nil
}

// checks that token is identifier and returns it, or a error
func (ce *CompilationEngine) getVarName() (string, error) {
id, err := ce.jt.Identifier()
Expand Down Expand Up @@ -497,7 +479,7 @@ func (ce *CompilationEngine) compileVarDec() error {
}

// Add this var to symbol table as well
ce.st.Define(name, type_, KIND_ARG)
ce.st.Define(name, type_, KIND_VAR)

// Advance to either the next "," and repeat the loop, or break and check for ";"
if err := ce.advance(); err != nil {
Expand Down Expand Up @@ -613,9 +595,6 @@ func (ce *CompilationEngine) compileSubroutineCall() error {
// 'do' subroutineCall ';'
// Eats it's own final character, so caller needn't immediately call advance() upon this function returning
func (ce *CompilationEngine) compileDo() error {
ce.openXMLTag("doStatement")
defer ce.closeXMLTag("doStatement")

if err := ce.checkForKeyword("do"); err != nil {
return SyntaxError(err)
}
Expand Down Expand Up @@ -711,9 +690,6 @@ func (ce *CompilationEngine) compileLet() error {
// 'while '(' expression ')' '{' statements '}'
// eats its own final token before returning, so calling function can expect to already be on the next token
func (ce *CompilationEngine) compileWhile() error {
ce.openXMLTag("whileStatement")
defer ce.closeXMLTag("whileStatement")

if err := ce.checkForKeyword("while"); err != nil {
return SyntaxError(err)
}
Expand Down Expand Up @@ -820,9 +796,6 @@ func (ce *CompilationEngine) compileIf() error {
return nil
}

ce.openXMLTag("ifStatement")
defer ce.closeXMLTag("ifStatement")

if err := ce.checkForKeyword("if"); err != nil {
return SyntaxError(err)
}
Expand Down Expand Up @@ -915,21 +888,15 @@ func (ce *CompilationEngine) compileExpression() error {
// '(' expression ')' | unaryOp term
func (ce *CompilationEngine) compileTerm() error {
if ce.jt.TokenType() == intConst {
ce.openXMLTag("integerConstant")
ic, err := ce.jt.IntVal()
_, err := ce.jt.IntVal()
if err != nil {
return SyntaxError(err)
}
ce.writeXMLData(strconv.Itoa(ic))
ce.closeXMLTag("integerConstant")
} else if ce.jt.TokenType() == strConst {
ce.openXMLTag("stringConstant")
sc, err := ce.jt.StringVal()
_, err := ce.jt.StringVal()
if err != nil {
return SyntaxError(err)
}
ce.writeXMLData(sc)
ce.closeXMLTag("stringConstant")
} else if ce.jt.TokenType() == keyWord {
kw, err := ce.jt.KeyWord()
if err != nil {
Expand All @@ -938,7 +905,6 @@ func (ce *CompilationEngine) compileTerm() error {
if !(kw == "true" || kw == "false" || kw == "null" || kw == "this") {
return SyntaxError(fmt.Errorf("term keyWord must be one of \"true\", \"false\", \"null\", or \"this\""))
}
return ce.marshaljt()
} else if ce.jt.TokenType() == symbol {
// '(' expression ')' | unaryOp term
sym, err := ce.jt.Symbol()
Expand Down
2 changes: 2 additions & 0 deletions Compiler/test/Seven/.gitignore
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Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
# ignore the files we generate with the compiler
Main.vm
23 changes: 23 additions & 0 deletions Compiler/test/Seven/Array.vm
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Original file line number Diff line number Diff line change
@@ -0,0 +1,23 @@
function Array.new 0
push argument 0
push constant 0
gt
not
if-goto IF_TRUE0
goto IF_FALSE0
label IF_TRUE0
push constant 2
call Sys.error 1
pop temp 0
label IF_FALSE0
push argument 0
call Memory.alloc 1
return
function Array.dispose 0
push argument 0
pop pointer 0
push pointer 0
call Memory.deAlloc 1
pop temp 0
push constant 0
return
102 changes: 102 additions & 0 deletions Compiler/test/Seven/Keyboard.vm
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Original file line number Diff line number Diff line change
@@ -0,0 +1,102 @@
function Keyboard.init 0
push constant 0
return
function Keyboard.keyPressed 0
push constant 24576
call Memory.peek 1
return
function Keyboard.readChar 2
push constant 0
call Output.printChar 1
pop temp 0
label WHILE_EXP0
push local 1
push constant 0
eq
push local 0
push constant 0
gt
or
not
if-goto WHILE_END0
call Keyboard.keyPressed 0
pop local 0
push local 0
push constant 0
gt
if-goto IF_TRUE0
goto IF_FALSE0
label IF_TRUE0
push local 0
pop local 1
label IF_FALSE0
goto WHILE_EXP0
label WHILE_END0
call String.backSpace 0
call Output.printChar 1
pop temp 0
push local 1
call Output.printChar 1
pop temp 0
push local 1
return
function Keyboard.readLine 5
push constant 80
call String.new 1
pop local 3
push argument 0
call Output.printString 1
pop temp 0
call String.newLine 0
pop local 1
call String.backSpace 0
pop local 2
label WHILE_EXP0
push local 4
not
not
if-goto WHILE_END0
call Keyboard.readChar 0
pop local 0
push local 0
push local 1
eq
pop local 4
push local 4
not
if-goto IF_TRUE0
goto IF_FALSE0
label IF_TRUE0
push local 0
push local 2
eq
if-goto IF_TRUE1
goto IF_FALSE1
label IF_TRUE1
push local 3
call String.eraseLastChar 1
pop temp 0
goto IF_END1
label IF_FALSE1
push local 3
push local 0
call String.appendChar 2
pop local 3
label IF_END1
label IF_FALSE0
goto WHILE_EXP0
label WHILE_END0
push local 3
return
function Keyboard.readInt 2
push argument 0
call Keyboard.readLine 1
pop local 0
push local 0
call String.intValue 1
pop local 1
push local 0
call String.dispose 1
pop temp 0
push local 1
return
17 changes: 17 additions & 0 deletions Compiler/test/Seven/Main.jack
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Original file line number Diff line number Diff line change
@@ -0,0 +1,17 @@
// This file is part of www.nand2tetris.org
// and the book "The Elements of Computing Systems"
// by Nisan and Schocken, MIT Press.
// File name: projects/11/Seven/Main.jack

/**
* Computes the value of 1 + (2 * 3) and prints the result
* at the top-left of the screen.
*/
class Main {

function void main() {
do Output.printInt(1 + (2 * 3));
return;
}

}
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