Compiler/Verifying syntax
< Compiler
Verifying Syntax
A Syntax Analyzer that verifies a token stream,
outputs a string "true" if the token stream matches the grammar requirement,
outputs a string "false" if the token stream does not match the grammar.
Task
The program reads input from a file of token stream,
reads it and outputs a string "true" if the token stream matches the grammar,
outputs a string "false" and error messages if the token stream does not match the grammar,
based on the grammar below. The grammar is written in Extended Backus-Naur Form (EBNF).
Grammar
stmt = expr ; expr = expr_level_2; expr_level_2 = expr_level_3 {"or" expr_level_3} ; expr_level_3 = expr_level_4 {"and" expr_level_4} ; expr_level_4 = ["not"] expr_level_5 [('=' | '<') expr_level_5] ; expr_level_5 = expr_level_6 {('+' | '-') expr_level_6} ; expr_level_6 = primary {('*' | '/') primary} ; primary = Identifier | Integer | '(' expr ')' | "true" | "false" ; Integer = Digit {Digit}; Identifier = Letter {Letter | Digit | '_'}; Digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ; Letter = "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" | "i" | "j" | "k" | "l" | "m" | "n" | "o" | "p" | "q" | "r" | "s" | "t" | "u" | "v" | "w" | "x" | "y" | "z" | "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" | "J" | "K" | "L" | "M" | "N" | "O" | "P" | "Q" | "R" | "S" | "T" | "U" | "V" | "W" | "X" | "Y" | "Z" ;