编译器代写: CS451/651 Project 2

CS451/651 Project 2 (Scanning) Swami Iyer

Ob jectives.

1. Support multiline comments.
2. Support additional tokens (reserved words, operators, and separators). 3. Support long and double literals.

In this project, you will only be updating the hand-crafted scanner, which means that the only program files you will be modifying under $j/j–/src/jminusminus are TokenInfo.java and Scanner.java. To compile (just scan for now) your j– programs, you need to run the j– command as follows:

$ $j/j–/bin/j– -t P.java

which only scans P.java and prints the tokens in the program along with the line number where each token appears. Problem 1. (Multiline Comment) Add support for multiline comment, where all the text from the ASCII characters /* to

the ASCII characters */ is ignored.

$ $j/j–/bin/j– -t tests/MultiLineComment.java

5 : public = public 5 : class = class

5 : <IDENTIFIER > = MultiLineComment 5 :{={

9 : public = public 9 : static = static

9 : void = void
9 : <IDENTIFIER > = main

9 :(=(
9 : <IDENTIFIER > = String

9 :[=[ 9 :]=]

9 : <IDENTIFIER > = args 9 :)=)

9 :{={ 13 :}=}

14 :}=}
15 : <EOF> = <EOF>

Problem 2. (Reserved Words) Add support for the following reserved words.

break case catch continue default do

double final finally for implements interface

long switch throw throws try

$ $j/j–/bin/j– -t tests/ReservedWords.java

1 : break = break 1 : case = case

1 : catch = catch
2 : continue = continue

2 : default = default 2 : do = do

3 : double = double 3 : final = final

3 : finally = finally
4 : for = for

4 : implements = implements 4 : interface = interface

5 : long = long
5 : switch = switch

5 : throw = throw
6 : throws = throws

6 : try = try
7 : <EOF> = <EOF>

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CS451/651 Project 2 (Scanning) Swami Iyer

Problem 3. (Operators) Add support for the following operators.

? ~ != / /= -= — *= % %=

>> >>= >>> >>>= >= << <<= < ^ ^=

| |= || & &=

$ $j/j–/bin/j– -t tests/Operators.java

1 :?=? 1 :~=~

1 : != = != 1 :/=/

1 : /= = /=
2 : -= = -=

2 : — = — 2 : *= = *=

2 :%=%
2 : %= = %=

3 : >> = >>
3 : >>= = >>=

3 : >>> = >>>
3 : >>>= = >>>=

3 : >= = >=
4 : << = <<

4 : <<= = <<= 4 :<=<

4 :^=^
4 : ^= = ^=

5 :|=|
5 : |= = |=

5 : || = || 5 :&=&

5 : &= = &=
6 : <EOF> = <EOF>

Problem 4. (Separators) Add support for the separator : (colon).

$ $j/j–/bin/j– -t tests/Separators.java

1 :;=; 2 ::=:

3 :,=, 4 :.=.

5 :[=[ 5 :{={

5 :(=( 5 :)=)

5 :}=} 5 :]=]

6 : <EOF> = <EOF>

Problem 5. (Literals) Add support for (just decimal for now) long and double literals.

<int_literal> = 0 | (1-9) {0-9} // decimal

<long_literal > = <int_literal > (l | L)

<digits> = (0-9) {0-9}

<suffix> = d | D

<double_literal > = <digits > . [<digits >] [<exponent >] [<suffix >] | . <digits > [<exponent >] [<suffix >]

| <digits > <exponent > [<suffix >]
| <digits > [<exponent >] <suffix >

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CS451/651 Project 2 (Scanning) Swami Iyer

$ $j/j–/bin/j– -t tests/Literals.java

1 : <INT_LITERAL > = 0 1 : <INT_LITERAL > = 2

1 : <INT_LITERAL > = 372

2 : <LONG_LITERAL >

= 1996l

2 : <LONG_LITERAL > = 777L 2 : <DOUBLE_LITERAL > = .3D

3 : <DOUBLE_LITERAL > = 3.14
3 : <DOUBLE_LITERAL > = 6.022137e+23

3 : <DOUBLE_LITERAL > = 1e-9d
4 : <EOF> = <EOF>

Files to Submit

1. j–.zip (j– source tree as a single zip file) 2. report.txt (project report)

Before you submit:

• Make sure you create the zip file j–.zip such that it only includes the source files and not the binaries, which can be done on the terminal as follows:

• Make sure your report isn’t too verbose, doesn’t contain lines that exceed 80 characters, and doesn’t contain spelling/grammatical mistakes

$ cd $j/j–

$ ant clean $ cd ..

$ tar -cvf j–.tar j–/* $ gzip j–.tar

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