Description
Objectives.
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.
Run the following command inside the $j directory to compile the j– compiler with your changes.
$ ant clean compile jar
Run the following command to compile (just scan for now) a j– program P.java using the j– compiler.
$ sh $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 : =
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
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CS451/651 Project 2 (Scanning) Swami Iyer
5 : long = long
5 : switch = switch
5 : throw = throw
6 : throws = throws
6 : try = try
7 : =
Problem 3. (Operators) Add support for the following operators. Note that some of the arithmetic, shift, and bitwise
operators were added to j– in Project 1.
? ~ != / /=
-= — *= % %=
>> >>= >>> >> >= >=
<< <<= < ^ ^= | |= || & &= $ $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 : =
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 : =
Problem 5. (Literals) Add support for (just decimal for now) long and double literals. Your are not allowed to use regular
expressions to scan literals.
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CS451/651 Project 2 (Scanning) Swami Iyer
< int_literal > = 0 | (1 -9) {0 -9} // decimal
< long_literal > = < int_literal > (l | L )
< digits > = (0 -9) {0 -9}
< exponent > = (e | E ) [(+ | -)] < digits >
< suffix > = d | D
< double_literal > = < digits > . [< digits >] [< exponent >] [< suffix >]
| . < digits > [< exponent >] [< suffix >]
| < digits > < exponent > [< suffix >]
| < digits > [< exponent >] < suffix >
$ $j /j – -/ bin /j – – -t tests / Literals . java
1 : < INT_LITERAL > = 0
1 : < INT_LITERAL > = 2
1 : < INT_LITERAL > = 372
2 : < LONG_LITERAL > = 1996 l
2 : < LONG_LITERAL > = 777 L
2 : < DOUBLE_LITERAL > = .3 D
3 : < DOUBLE_LITERAL > = 3.14
3 : < DOUBLE_LITERAL > = 6.022137 e +23
3 : < DOUBLE_LITERAL > = 1e -9 d
4 : =
Files to Submit
1. j–.tar.gz (j– source tree as a single gzip file)
2. report.txt (project report)
Before you submit:
• Make sure you create the gzip file j–.tar.gz such that it only includes the source files and not the binaries, which
can be done on the terminal as follows:
$ cd $j /j —
$ ant clean
$ cd ..
$ tar – czvf j – -. tar j – -/*
• Make sure your report uses the given template, isn’t too verbose, doesn’t contain lines that exceed 80 characters,
and doesn’t contain spelling mistakes
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