华南理工大学计算机全英班编译原理实验1

Compiler Construction Experiment 1 Implementing a Scanner for TINY+ You are to write a lexical analyzer/scanner for the language TINY+. Goals 1The input of the scanner is a source code file and the output of the scanner is a stream of tokens. 2Your scanner should go for longest possible match i.e. a string ‘:=’ is to be identified as ‘ass-symbol’ rather than ‘:’ and ‘=’. 3Token is represented as (Kind, Value). We use the following symbols to denote different kinds of tokens KEY denotes reserved words SYM denotes special symbols ID denotes identifiers NUM denotes numeric constants STR denotes string constants 4Check lexical errors: giving meaning error messages and the lines where errors occur. The kinds of lexical errors are: Illegal character, that is, scanner may recognize a character that is not in the alphabet of TINY+, such as $ is an illegal character The right bracket of a STRING is lost, such as ' scanner The right delimiter of a comment is lost, such as: {this is an example Requirements 1Write your program in C or C++ 2This experiment must be finished in 4 periods. You will submit a report and the source code Example output for some TINY+ programs Test1 or and int bool char while do if then else end repeat until read write , ; := + - * / ( ) = a2c 123 'EFG' The scanner should give the outputs: (KEY, or) (KEY, and) (KEY, int) (KEY, bool) (KEY, char) (KEY, while) (KEY, do) (KEY, if) (KEY, then) (KEY, else) (KEY, end) (KEY, repeat) (KEY, until) (KEY, read) (KEY, write) (SYM, ,) (SYM, ;) (SYM, :=) (SYM, +) (SYM, -) (SYM, *) (SYM, /) (SYM, ( ) (SYM, )) (SYM, ) (SYM, =) (ID, a2c) (NUM, 123) (STR, EFG) Test2 {this is an example} int A,B; bool C1, C2, C3; char D; D:= 'scanner'; while A<=B do A:=A*2 end The scanner should give the outputs: (KEY, int) (ID, A) (SYM, ,) (ID, B) (SYM, ;) (KEY, bool) (ID, C1) (SYM, ,) (ID, C2) (SYM, ,) (ID, C3