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Language Grammar

grammar CashScript;

sourceFile
: pragmaDirective* contractDefinition EOF
;

pragmaDirective
: 'pragma' pragmaName pragmaValue ';'
;

pragmaName
: 'cashscript'
;

pragmaValue
: versionConstraint versionConstraint?
;

versionConstraint
: versionOperator? VersionLiteral
;

versionOperator
: '^' | '~' | '>=' | '>' | '<' | '<=' | '='
;

contractDefinition
: 'contract' Identifier parameterList '{' functionDefinition* '}'
;

functionDefinition
: 'function' Identifier parameterList '{' statement* '}'
;

parameterList
: '(' (parameter (',' parameter)* ','?)? ')'
;

parameter
: typeName Identifier
;

block
: '{' statement* '}'
| statement
;

statement
: variableDefinition
| tupleAssignment
| assignStatement
| timeOpStatement
| requireStatement
| ifStatement
| consoleStatement
;

variableDefinition
: typeName modifier* Identifier '=' expression ';'
;

tupleAssignment
: typeName Identifier ',' typeName Identifier '=' expression ';'
;

assignStatement
: Identifier '=' expression ';'
;

timeOpStatement
: 'require' '(' TxVar '>=' expression (',' StringLiteral)? ')' ';'
;

requireStatement
: 'require' '(' expression (',' StringLiteral)? ')' ';'
;

ifStatement
: 'if' '(' expression ')' ifBlock=block ('else' elseBlock=block)?
;

consoleStatement
: 'console.log' consoleParameterList ';'
;

consoleParameter
: Identifier
| StringLiteral
| NumberLiteral
| HexLiteral
| BooleanLiteral
;

consoleParameterList
: '(' (consoleParameter (',' consoleParameter)* ','?)? ')'
;

functionCall
: Identifier expressionList // Only built-in functions are accepted
;

expressionList
: '(' (expression (',' expression)* ','?)? ')'
;

expression
: '(' expression ')' # Parenthesised
| typeName '(' castable=expression (',' size=expression)? ','? ')' # Cast
| functionCall # FunctionCallExpression
| 'new' Identifier expressionList #Instantiation
| expression '[' index=NumberLiteral ']' # TupleIndexOp
| scope='tx.outputs' '[' expression ']' op=('.value' | '.lockingBytecode' | '.tokenCategory' | '.nftCommitment' | '.tokenAmount') # UnaryIntrospectionOp
| scope='tx.inputs' '[' expression ']' op=('.value' | '.lockingBytecode' | '.outpointTransactionHash' | '.outpointIndex' | '.unlockingBytecode' | '.sequenceNumber' | '.tokenCategory' | '.nftCommitment' | '.tokenAmount') # UnaryIntrospectionOp
| expression op=('.reverse()' | '.length') # UnaryOp
| left=expression op='.split' '(' right=expression ')' # BinaryOp
| op=('!' | '-') expression # UnaryOp
| left=expression op=('*' | '/' | '%') right=expression # BinaryOp
| left=expression op=('+' | '-') right=expression # BinaryOp
// | expression ('>>' | '<<') expression --- OP_LSHIFT & RSHIFT are disabled in BCH Script
| left=expression op=('<' | '<=' | '>' | '>=') right=expression # BinaryOp
| left=expression op=('==' | '!=') right=expression # BinaryOp
| left=expression op='&' right=expression # BinaryOp
| left=expression op='^' right=expression # BinaryOp
| left=expression op='|' right=expression # BinaryOp
| left=expression op='&&' right=expression # BinaryOp
| left=expression op='||' right=expression # BinaryOp
| '[' (expression (',' expression)* ','?)? ']' # Array
| NullaryOp # NullaryOp
| Identifier # Identifier
| literal # LiteralExpression
;

modifier
: 'constant'
;

literal
: BooleanLiteral
| numberLiteral
| StringLiteral
| DateLiteral
| HexLiteral
;

numberLiteral
: NumberLiteral NumberUnit?
;

typeName
: 'int' | 'bool' | 'string' | 'pubkey' | 'sig' | 'datasig' | Bytes
;

VersionLiteral
: [0-9]+ '.' [0-9]+ '.' [0-9]+
;

BooleanLiteral
: 'true' | 'false'
;

NumberUnit
: 'satoshis' | 'sats' | 'finney' | 'bits' | 'bitcoin'
| 'seconds' | 'minutes' | 'hours' | 'days' | 'weeks'
;

NumberLiteral
: [-]?[0-9]+ ([eE] [0-9]+)?
;

Bytes
: 'bytes' Bound? | 'byte'
;

Bound
: [1-9] [0-9]*
;

StringLiteral
: '"' ('\\"' | ~["\r\n])*? '"'
| '\'' ('\\\'' | ~['\r\n])*? '\''
;

DateLiteral
: 'date(' StringLiteral ')'
;

HexLiteral
: '0' [xX] [0-9A-Fa-f]*
;

TxVar
: 'tx.age'
| 'tx.time'
;

NullaryOp
: 'this.activeInputIndex'
| 'this.activeBytecode'
| 'tx.inputs.length'
| 'tx.outputs.length'
| 'tx.version'
| 'tx.locktime'
;

Identifier
: [a-zA-Z] [a-zA-Z0-9_]*
;

WHITESPACE
: [ \t\r\n\u000C]+ -> skip
;

COMMENT
: '/*' .*? '*/' -> channel(HIDDEN)
;

LINE_COMMENT
: '//' ~[\r\n]* -> channel(HIDDEN)
;