expr.peg

# A simple languaAge for experimenting with ASTs in Rust
# 
# Usage:
#   $ make clean && make && ./check_parser.sh to verify all files in the examples folder
#
#   $ make clean && make && ./check_parser.sh <file-name> to check a paritcular file.
#

CompilationUnit <- Whitespace Expr* Eof

Expr <- AssignExpr

AssignExpr <- LogicalOrExpr (ASSIGN_op LogicalOrExpr)*

LogicalOrExpr <- LogicalAndExpr (LOGICALOR_op LogicalAndExpr)*

LogicalAndExpr <- RelationalExpr (LOGICALAND_op RelationalExpr)*

RelationalExpr <- BitExpr (RELATIONAL_op BitExpr)*

BitExpr <- BitShiftExpr (BIT_op BitShiftExpr)*

BitShiftExpr <- AdditiveExpr (BITSHIFT_op AdditiveExpr)*

AdditiveExpr <- MultiplicativeExpr (ADDITIVE_op MultiplicativeExpr)*

MultiplicativeExpr <- UnaryExpr (MULTIPLICATIVE_op MultiplicativeExpr)*

UnaryExpr <- UNARYPLUS_op UnaryExpr
            / UNARYMINUS_opUnaryExpr
            / BITWISENOT_op UnaryExpr
            / LOGICALNOT_op UnaryExpr
            / PREFIXINC_op UnaryExpr
            / PREFIXDEC_op UnaryExpr
            / POSTFIXINC_op UnaryExpr
            / POSTFIXDEC_op UnaryExpr
            / LPAREN Expr RPAREN
            / PrintExpr
            / Identifier
            / IntegerLiteral
            / BoolLiteral


PrintExpr <- PRINT_keyword LPAREN Expr RPAREN

Identifier <- [a-zA-Z_][a-zA-Z_0-9]* Whitespace

IntegerLiteral <- [0-9]+ Whitespace
BoolLiteral <- FALSE_const / TRUE_const

FALSE_const <- 'false' Whitespace
TRUE_const <- 'true' Whitespace

ASSIGN_op <- ('=' / '+=' / '-=' / '*=' / '/=' / '%=' / '&=' / '|=' / '^=' / '<<=' / '>>=') Whitespace
LOGICALOR_op <- '||' Whitespace
LOGICALAND_op <- '&&' Whitespace
RELATIONAL_op <- ('<=' / '<' / '>=' / '>' / '==' / '!=') Whitespace
BIT_op <- ('&' / '|' / '^') Whitespace
BITSHIFT_op <- ('<<' / '>>') Whitespace
ADDITIVE_op <- ('+' / '-') Whitespace
MULTIPLICATIVE_op <- ('*' / '/' / '%') Whitespace
BITWISENOT_op <- '~' Whitespace
LOGICALNOT_op <- '!' Whitespace
PREFIXINC_op <- '++' Whitespace
PREFIXDEC_op <- '--' Whitespace
POSTFIXINC_op <- '++' Whitespace
POSTFIXDEC_op <- '--' Whitespace

UNARYPLUS_op <- '+' Whitespace
UNARYMINUS_opUnaryExpr <- '-' Whitespace

PRINT_keyword <- 'print' Whitespace

LPAREN <- '(' Whitespace
RPAREN <- ')' Whitespace

comment <- '//' ([^\n])*
Whitespace <- ([ \t\n] / comment)*

Eof <- !.