Smalltalk
project代做 | Smalltalk – 这个项目是Smalltalk代写的代写题目
1. Overview
Smalltalk is a pure object-oriented language,where everything is an object, and all actions are accomplished by sending messages,even for what in other languages would be control structures.Inthis project we will be using Gnu Smalltalk, the Smalltalk for those who can type.References : https://ftp.gnu.org/gnu/smalltalk/ https://www.gnu.org/software/smalltalk/ https://www.gnu.org/software/smalltalk/manual/ https://www.gnu.org/software/smalltalk/manual-base/ https://learnxinyminutes.com/docs/smalltalk/ http://www.angelfire.com/tx4/cus/notes/smalltalk.html
2. RunningGnu Smalltalk interactively
Smalltalk is an interpretibve language and can be run from the command line or by ascriptl Torun gst ,add the following to your $HOME/.bash_profile : export PATH=$PATH:/afs/cats.ucsc.edu/courses/cse112-wm/usr/smalltalk/bin When running gst interactively,use the command rlwrap to gain access to the read- line arrow keys so that you can recover earlier typed lines.Notice the unexpected(?) operator precedence.Example : -bash-$ rlwrap gst GNU Smalltalk ready st> 2+36.* 30 st> 2raisedTo: 128. 340282366920938463463374607431768211456 st> (-1 arcCos * -1 sqrt) exp + 1. (0.0+0.00000000000000012246467991473532i) st> 5sqrt + 1 / 2.
st> ^D
Instead of explicitly typing rlwrap every time you start gst interactively,create the command wgst by putting the following in in your $HOME/.bash_profile : alias wgst=rlwrap gst
3. Theprogrammbint.st
Complete the implementation of mbint.st ,aSmalltalk implementation of the Basic interpreter from previous projects.The following classes are of interest :
Object subclass: Debug Asingleton class with a debug flag whichcan be turned on from the command line.Multiple -d options increase the level of debugging for more information.
Object subclass: MiniBasic The root class to hold methods that are usefully inherited by other classes. unimplemented: is used to print error messages for classes not fully
implemented. prefix is used by the multiple printOn: methods to label the
output when self is printed.
MiniBasic subclass: Expr Expr is the abstract base class from whichall other expression classes inherit.
Expr subclass: NumExpr Holds numbers of class FloaatD or Complex .Complex numbers are not specifi- cally handled, but maybeproduced by expressions suchas (-1 sqrt).
Expr subclass: VarExpr Eachinstance represents a simple variable.The class variable varDict holds the symbol table.
Expr subclass: UnopExpr Implements unary operators (functions). The value method is to be imple- mented.
Expr subclass: BinopExpr Implements binary operators.The value method is to be implemented.
Expr subclass: ArrayExpr Holds the arraytable as a class varible and arraynames as instances.
Expr extend Is an extension of Expr placed later in the file so that it can refer to its sub- classes. Expr>>parse: accepts the arrayprefix notation of the intermediate format and produces the proper class instances.
MiniBasic subclass: Stmt Is the root of the statment interpreters.The class variable stmtNr contains the number of the next statement to be implemented. labelDict is to contain the labels from the original program as keys and the corresponding statement numbers as values.
Stmt subclass: DimStmt Interprets the dim statement.
Stmt subclass: LetStmt Evaluates an expression and assigns it to the appriate variable.
Stmt subclass: GotoStmt The interp method assign a new value to stmtNr.
Stmt subclass: IfStmt Evaluates the expression. If true,behaves like the goto statement.
Stmt subclass: InputStmt Reads input for eachvariable mentioned on the input line and stores its value in the appropriate symbol table.Ifthe token read isNumber it is returned. oth- erwise NaN ( 0.0/0.0 )isreturned.
Stmt subclass: PrintStmt Prints the list of arguments in readable format.
Stmt subclass: NullStmt Adummy slot used when the intermediate language has an empty statement. interp does nothing.
Stmt extend Is an extension of Stmt that can refer to the subclasses. Stmt>>parse converts the intermediate langage into an object structure.
MiniBasic subclass: Interpreter Initializes the progra structure and controls the Stmt interpreters. Inter- preter>>print is for debugging only.
Object subclass: Main Takes care of scanning the command line option and operand, produces suit- able error messages if appropriate,and calls the interpreter.
4. Whatto submit
Submit mbint.st and README .Also PARTNER if doing pair programming.