Grammar for the MysoreScript language. More...

#include <grammar.hh>

Collaboration diagram for Parser::MysoreScriptGrammar:

Static Public Member Functions
static const MysoreScriptGrammar &	get ()
	Returns a singleton instance of this grammar. More...

Public Attributes
Rule	whitespace = ' '_E \| '\t' \| nl('\n')
	Whitespace: spaces, tabs, newlines. More...

Rule	comment
	Comments, including tracking newlines inside comments via the whitespace rule. More...

Rule	ignored = *(comment \| whitespace)
	Rule for treating both comments and whitespace as ignored tokens. More...

ExprPtr	digit = '0'_E - '9'
	Digits are things in the range 0-9. More...

Rule	num = -("+-"_S) >> +digit
	Numbers are one or more digits, optionally prefixed with its sign. More...

Rule	val = num \| '(' >> arith_expr >> ')'
	Values are either numbers or expressions in brackets (highest precedence). More...

Rule	mul_op = mul >> '*' >> val
	Multiply operations are values or multiply, or divide operations, followed by a multiply symbol, followed by a value. More...

Rule	div_op = mul >> '/' >> val
	Divide operations follow the same syntax as multiply. More...

Rule	mul = mul_op \| div_op \| val
	Multiply-precedence operations are either multiply or divide operations, or simple values (numbers of parenthetical expressions). More...

Rule	add_op = arith_expr >> '+' >> arith_expr
	Add operations can have any expression on the left (including other add expressions), but only higher-precedence operations on the right. More...

Rule	sub_op = arith_expr >> '-' >> arith_expr
	Subtract operations follow the same structure as add. More...

Rule	ne_cmp = arith_expr >> "!=" >> arith_expr
	Not-equal comparison. More...

Rule	eq_cmp = arith_expr >> "==" >> arith_expr
	Equal comparison. More...

Rule	lt_cmp = arith_expr >> '<' >> arith_expr
	Less-than comparison. More...

Rule	gt_cmp = arith_expr >> '>' >> arith_expr
	Greater-than comparison. More...

Rule	le_cmp = arith_expr >> "<=" >> arith_expr
	Less-than-or-equal comparison. More...

Rule	ge_cmp = arith_expr >> ">=" >> arith_expr
	Greater-than-or-equal comparison. More...

Rule	cmp = eq_cmp \| ne_cmp \| lt_cmp \| gt_cmp \| le_cmp \| ge_cmp
	General rule for comparisons. More...

Rule	arith_expr = add_op \| sub_op \| mul \| cmp \| expression
	Expressions can be any of the other types. More...

ExprPtr	character = term(("\\\""_E \| !ExprPtr('"') >> (nl('\n') \| any())))
	A character in a string. More...

Rule	string_body = *character
	The body of a string. More...

Rule	string = term('"' >> string_body >> '"')
	Strings any characters, enclosed in quotes. More...

ExprPtr	letter = (('a'_E - 'z') \| ('A'_E - 'Z'))
	Letters - valid characters for the start of an identifier. More...

Rule	identifier = term(letter >> *(letter \| digit))
	Identifiers are a letter followed by zero or more alphanumeric characters. More...

Rule	argList = '('_E >> -(identifier >> *(',' >> identifier)) >> ')'
	Argument list. More...

Rule	closure
	A closure starts with the keyword 'func', followed by a function name, a list of arguments in brackets and a list of statements in braces. More...

Rule	variable = identifier
	Variable references are single identifiers. More...

Rule	assignment = variable >> '=' >> expression
	Assignments are variables, followed by a single equals sign, and then the expression to assign to the variable. More...

Rule	callArgList = '('_E >> -(expression >> *(',' >> expression)) >> ')'
	The argument list for a call. More...

Rule	call = callable >> -('.'_E >> identifier) >> callArgList
	A call is something that is callable, followed eventually by an argument list. More...

Rule	callable
	Callable expression. More...

Rule	expression
	All of the valid kinds of expression. More...

Rule	newExpr = "new"_E >> identifier
	A `new` expression: the keyword new followed by a class name. More...

Rule	decl = "var"_E >> identifier >> -('='_E >> expression) >> ';'
	A variable declaration, optionally with an initialiser. More...

Rule	ret = "return"_E >> expression >> ';'
	A return statement. More...

Rule	ifStatement
	An if statement, with a condition in brackets followed by the body in braces. More...

Rule	whileLoop
	A while loop, with the condition in brackets followed by the body in braces. More...

Rule	cls
	Classes are the keyword class, followed by the class name and optionally a superclass. More...

Rule	statement
	All valid statement types. More...

Rule	statements = *(statement)
	A list of statements: the top-level for programs in this grammar. More...

Detailed Description

Grammar for the MysoreScript language.

Definition at line 16 of file grammar.hh.

Member Function Documentation

§ get()

static const MysoreScriptGrammar& Parser::MysoreScriptGrammar::get ( )

inlinestatic

Returns a singleton instance of this grammar.

Definition at line 220 of file grammar.hh.

Member Data Documentation

§ add_op

Rule Parser::MysoreScriptGrammar::add_op = arith_expr >> '+' >> arith_expr

Add operations can have any expression on the left (including other add expressions), but only higher-precedence operations on the right.

Definition at line 67 of file grammar.hh.

§ argList

Rule Parser::MysoreScriptGrammar::argList = '('_E >> -(identifier >> *(',' >> identifier)) >> ')'

Argument list.

Zero or more comma-separated arguments, wrapped in brackets.

Definition at line 130 of file grammar.hh.

§ arith_expr

Rule Parser::MysoreScriptGrammar::arith_expr = add_op | sub_op | mul | cmp | expression

Expressions can be any of the other types.

Definition at line 103 of file grammar.hh.

§ assignment

Rule Parser::MysoreScriptGrammar::assignment = variable >> '=' >> expression

Assignments are variables, followed by a single equals sign, and then the expression to assign to the variable.

Definition at line 145 of file grammar.hh.

§ call

Rule Parser::MysoreScriptGrammar::call = callable >> -('.'_E >> identifier) >> callArgList

A call is something that is callable, followed eventually by an argument list.

If the callable expression is followed by a dot and a method name, then this is a method invocation, otherwise the expression on the left is assumed to be a closure and is invoked directly.

Definition at line 158 of file grammar.hh.

§ callable

Rule Parser::MysoreScriptGrammar::callable

Initial value:

call

Callable expression.

This is the same as an expression, but with the call at the end so that each of the other possibilities will be tried before hitting left recursion.

Definition at line 164 of file grammar.hh.

§ callArgList

Rule Parser::MysoreScriptGrammar::callArgList = '('_E >> -(expression >> *(',' >> expression)) >> ')'

The argument list for a call.

This is a separate rule to allow automatic AST construction to distinguish between the expressions that are part of the argument list from others in the call.

Definition at line 151 of file grammar.hh.

§ character

ExprPtr Parser::MysoreScriptGrammar::character = term(("\\\""_E | !ExprPtr('"') >> (nl('\n') | any())))

A character in a string.

Matches anything except the closing quote.

Definition at line 107 of file grammar.hh.

§ closure

Rule Parser::MysoreScriptGrammar::closure

Initial value:

= "func"_E >> identifier >> argList >>

'{' >> statements >> '}'

A closure starts with the keyword 'func', followed by a function name, a list of arguments in brackets and a list of statements in braces.

Definition at line 135 of file grammar.hh.

§ cls

Rule Parser::MysoreScriptGrammar::cls

Initial value:

= "class"_E >> identifier >> -(':'_E >> identifier) >> '{'

>> *decl >> *closure >> '}'

Classes are the keyword class, followed by the class name and optionally a superclass.

Instance variables must be declared first, then methods.

Definition at line 205 of file grammar.hh.

§ cmp

General rule for comparisons.

Matches one of the comparison types above.

Definition at line 99 of file grammar.hh.

§ comment

Rule Parser::MysoreScriptGrammar::comment

Initial value:

= ("/*"_E >>
                       (*(!ExprPtr("*/") >> (nl('\n') | any()))) >>
                       "*/") |
                       "//"_E >> *(!(ExprPtr("\n")) >> any()) >> nl('\n')

Comments, including tracking newlines inside comments via the whitespace rule.

Definition at line 26 of file grammar.hh.

§ decl

Rule Parser::MysoreScriptGrammar::decl = "var"_E >> identifier >> -('='_E >> expression) >> ';'

A variable declaration, optionally with an initialiser.

Definition at line 184 of file grammar.hh.

§ digit

ExprPtr Parser::MysoreScriptGrammar::digit = '0'_E - '9'

Digits are things in the range 0-9.

Definition at line 37 of file grammar.hh.

§ div_op

Rule Parser::MysoreScriptGrammar::div_op = mul >> '/' >> val

Divide operations follow the same syntax as multiply.

Definition at line 57 of file grammar.hh.

§ eq_cmp

Rule Parser::MysoreScriptGrammar::eq_cmp = arith_expr >> "==" >> arith_expr

Equal comparison.

Definition at line 79 of file grammar.hh.

§ expression

Rule Parser::MysoreScriptGrammar::expression

Initial value:

string

All of the valid kinds of expression.

Note that the order places calls first, as greedy matching will try cause them to then be matched in the callable order (which places call last) and then parse the argument list, but would just successfully parse an expression and stop if call were not first here. Note also that expression types that start with a keyword are placed before those that (may) begin with identifiers so that we can trivially disambiguate these cases.

Definition at line 175 of file grammar.hh.

§ ge_cmp

Rule Parser::MysoreScriptGrammar::ge_cmp = arith_expr >> ">=" >> arith_expr

Greater-than-or-equal comparison.

Definition at line 95 of file grammar.hh.

§ gt_cmp

Rule Parser::MysoreScriptGrammar::gt_cmp = arith_expr >> '>' >> arith_expr

Greater-than comparison.

Definition at line 87 of file grammar.hh.

§ identifier

Rule Parser::MysoreScriptGrammar::identifier = term(letter >> *(letter | digit))

Identifiers are a letter followed by zero or more alphanumeric characters.

Definition at line 125 of file grammar.hh.

§ ifStatement

Rule Parser::MysoreScriptGrammar::ifStatement

Initial value:

= "if"_E >> '(' >> expression >> ')' >>

'{' >> statements >> '}'

An if statement, with a condition in brackets followed by the body in braces.

Definition at line 193 of file grammar.hh.

§ ignored

Rule Parser::MysoreScriptGrammar::ignored = *(comment | whitespace)

Rule for treating both comments and whitespace as ignored tokens.

Definition at line 33 of file grammar.hh.

§ le_cmp

Rule Parser::MysoreScriptGrammar::le_cmp = arith_expr >> "<=" >> arith_expr

Less-than-or-equal comparison.

Definition at line 91 of file grammar.hh.

§ letter

ExprPtr Parser::MysoreScriptGrammar::letter = (('a'_E - 'z') | ('A'_E - 'Z'))

Letters - valid characters for the start of an identifier.

Definition at line 120 of file grammar.hh.

§ lt_cmp

Rule Parser::MysoreScriptGrammar::lt_cmp = arith_expr >> '<' >> arith_expr

Less-than comparison.

Definition at line 83 of file grammar.hh.

§ mul

Rule Parser::MysoreScriptGrammar::mul = mul_op | div_op | val

Multiply-precedence operations are either multiply or divide operations, or simple values (numbers of parenthetical expressions).

Definition at line 62 of file grammar.hh.

§ mul_op

Rule Parser::MysoreScriptGrammar::mul_op = mul >> '*' >> val

Multiply operations are values or multiply, or divide operations, followed by a multiply symbol, followed by a value.

The sides can never be add or subtract operations, because they have lower precedence and so can only be parents of multiply or divide operations (or children via parenthetical expressions), not direct children.

Definition at line 53 of file grammar.hh.

§ ne_cmp

Rule Parser::MysoreScriptGrammar::ne_cmp = arith_expr >> "!=" >> arith_expr

Not-equal comparison.

Definition at line 75 of file grammar.hh.

§ newExpr

Rule Parser::MysoreScriptGrammar::newExpr = "new"_E >> identifier

A new expression: the keyword new followed by a class name.

Definition at line 180 of file grammar.hh.

§ num

Rule Parser::MysoreScriptGrammar::num = -("+-"_S) >> +digit

Numbers are one or more digits, optionally prefixed with its sign.

Definition at line 41 of file grammar.hh.

§ ret

Rule Parser::MysoreScriptGrammar::ret = "return"_E >> expression >> ';'

A return statement.

Definition at line 188 of file grammar.hh.

§ statement

Rule Parser::MysoreScriptGrammar::statement

Initial value:

((assignment | expression) >> ';')

All valid statement types.

Statements that are disambiguated by keywords are first. All expressions are valid statements.

Definition at line 211 of file grammar.hh.

§ statements

Rule Parser::MysoreScriptGrammar::statements = *(statement)

A list of statements: the top-level for programs in this grammar.

Definition at line 216 of file grammar.hh.

§ string

Rule Parser::MysoreScriptGrammar::string = term('"' >> string_body >> '"')

Strings any characters, enclosed in quotes.

Definition at line 116 of file grammar.hh.

§ string_body

Rule Parser::MysoreScriptGrammar::string_body = *character

The body of a string.

An AST builder can use this to get just the characters in the string, without the enclosing quotes.

Definition at line 112 of file grammar.hh.

§ sub_op

Rule Parser::MysoreScriptGrammar::sub_op = arith_expr >> '-' >> arith_expr

Subtract operations follow the same structure as add.

Definition at line 71 of file grammar.hh.

§ val

Rule Parser::MysoreScriptGrammar::val = num | '(' >> arith_expr >> ')'

Values are either numbers or expressions in brackets (highest precedence).

Definition at line 45 of file grammar.hh.

§ variable

Rule Parser::MysoreScriptGrammar::variable = identifier

Variable references are single identifiers.

Definition at line 140 of file grammar.hh.

§ whileLoop

Rule Parser::MysoreScriptGrammar::whileLoop

Initial value:

= "while"_E >> '(' >> expression >> ')' >>

'{' >> statements >> '}'

A while loop, with the condition in brackets followed by the body in braces.

Definition at line 199 of file grammar.hh.

§ whitespace

Rule Parser::MysoreScriptGrammar::whitespace = ' '_E | '\t' | nl('\n')

Whitespace: spaces, tabs, newlines.

Definition at line 21 of file grammar.hh.

The documentation for this struct was generated from the following file:

grammar.hh

Static Public Member Functions

Public Attributes

Detailed Description

Member Function Documentation

§ get()

Member Data Documentation

§ add_op

§ argList

§ arith_expr

§ assignment

§ call

§ callable

§ callArgList

§ character

§ closure

§ cls

§ cmp

§ comment

§ decl

§ digit

§ div_op

§ eq_cmp

§ expression

§ ge_cmp

§ gt_cmp

§ identifier

§ ifStatement

§ ignored

§ le_cmp

§ letter

§ lt_cmp

§ mul

§ mul_op

§ ne_cmp

§ newExpr

§ num

§ ret

§ statement

§ statements

§ string

§ string_body

§ sub_op

§ val

§ variable

§ whileLoop

§ whitespace