ChaiScript/grammar/chaiscript.ebnf
leftibot 1ce4a81b98 Merge upstream/develop into fix/issue-677-add-strong-typedefs
Resolve merge conflicts with ChaiScript:develop. Upstream added
nested namespace support (#675), grammar railroad diagrams (#673),
and WASM exception support (#689). Conflicts in chaiscript_common.hpp,
chaiscript_eval.hpp, and chaiscript_parser.hpp resolved by keeping
both Using and Namespace_Block AST node types.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-14 15:35:06 -06:00

178 lines
5.9 KiB
EBNF

/*
* ChaiScript Grammar EBNF for Railroad Diagram Generation
*
* View as navigable railroad diagrams at:
* https://www.bottlecaps.de/rr/ui (IPv6)
* https://rr.red-dove.com/ui (IPv4)
*
* Copy and paste this file into the 'Edit Grammar' tab, then
* click 'View Diagram'.
*
* This grammar uses the notation accepted by
* https://github.com/GuntherRademacher/rr :
* - "::=" as rule separator
* - no semicolon at end of rule
* - "?" "+" "*" for repetition
* - C comments
*/
/* ---- Top-level ---- */
statements ::= ( def | try | if | while | class | for
| switch | return | break | continue
| equation | block | eol )+
/* ---- Functions ---- */
def ::= "def" id ( "::" id )? "(" decl_arg_list ")" eol*
( ":" guard )? eol* block
lambda ::= "fun" ( "[" id_arg_list "]" )? "(" decl_arg_list ")" eol* block
guard ::= operator
/* ---- Exception handling ---- */
try ::= "try" eol* block catch* finally?
catch ::= "catch" ( "(" arg ")" )? eol* block
finally ::= "finally" eol* block
/* ---- Control flow ---- */
if ::= "if" "(" equation ( eol equation )? ")" eol* block
( "else" ( if | eol* block ) )*
while ::= "while" "(" operator ")" eol* block
for ::= "for" "(" ( for_guards | equation ":" equation ) ")" eol* block
for_guards ::= equation eol equation eol equation
switch ::= "switch" "(" operator ")" eol* "{" ( case | default )+ "}"
case ::= "case" "(" operator ")" eol* block
default ::= "default" eol* block
/* ---- Classes ---- */
class ::= "class" id ( ":" id )? eol* class_block
class_block ::= "{" class_statements* "}"
class_statements ::= def | var_decl | eol
/* ---- Blocks & flow keywords ---- */
block ::= "{" statements* "}"
return ::= "return" operator?
break ::= "break"
continue ::= "continue"
/* ---- Line termination ---- */
eol ::= "\n" | "\r\n" | ";"
/* ---- Equations & operators ---- */
equation ::= operator ( ( "=" | ":=" | "+=" | "-=" | "*=" | "/="
| "%=" | "<<=" | ">>=" | "&=" | "^=" | "|=" )
equation )?
operator ::= prefix
| value
| operator binary_operator operator
| operator "?" operator ":" operator
prefix ::= ( "++" | "--" | "-" | "+" | "!" | "~" ) operator
binary_operator ::= "||" | "&&"
| "|" | "^" | "&"
| "==" | "!="
| "<" | "<=" | ">" | ">="
| "<<" | ">>"
| "+" | "-"
| "*" | "/" | "%"
/* ---- Values & access ---- */
value ::= var_decl | dot_fun_array | prefix
dot_fun_array ::= ( lambda | num | quoted_string
| single_quoted_string | raw_string
| paren_expression | inline_container
| id )
( fun_call | array_call | dot_access )*
fun_call ::= "(" arg_list ")"
array_call ::= "[" operator "]"
dot_access ::= "." id
/* ---- Variable declarations ---- */
var_decl ::= ( "auto" | "var" | "const" ) ( reference | id )
| "global" ( reference | id )
| "attr" id ( "::" id )?
reference ::= "&" id
/* ---- Parenthesised & inline containers ---- */
paren_expression ::= "(" operator ")"
inline_container ::= "[" container_arg_list "]"
container_arg_list ::= value_range
| map_pair ( "," map_pair )*
| operator ( "," operator )*
value_range ::= operator ".." operator
map_pair ::= operator ":" operator
/* ---- String literals ---- */
quoted_string ::= '"' ( char | escape | interpolation )* '"'
single_quoted_string ::= "'" ( char | escape ) "'"
raw_string ::= 'R"' delimiter? "(" char* ")" delimiter? '"'
delimiter ::= [a-zA-Z0-9_]+
interpolation ::= "${" equation "}"
/* ---- Escape sequences ---- */
escape ::= "\" ( "'" | '"' | "?" | "\" | "a" | "b"
| "f" | "n" | "r" | "t" | "v" | "$"
| "0"
| "x" hex_digit+
| "u" hex_digit hex_digit hex_digit hex_digit
| "U" hex_digit hex_digit hex_digit hex_digit
hex_digit hex_digit hex_digit hex_digit
| octal_digit+ )
/* ---- Argument lists ---- */
id_arg_list ::= id ( "," id )*
decl_arg_list ::= ( arg ( "," arg )* )?
arg_list ::= ( equation ( "," equation )* )?
arg ::= id id?
/* ---- Identifiers ---- */
id ::= ( [a-zA-Z_] [a-zA-Z0-9_]* )
| ( "`" [^`]+ "`" )
| "true" | "false"
| "Infinity" | "NaN"
| "_"
| "__LINE__" | "__FILE__" | "__FUNC__" | "__CLASS__"
/* ---- Numeric literals ---- */
num ::= hex | binary | float | integer
hex ::= "0" ( "x" | "X" ) [0-9a-fA-F]+ int_suffix*
binary ::= "0" ( "b" | "B" ) [01]+ int_suffix*
float ::= [0-9]+ "." [0-9]+ ( ( "e" | "E" ) ( "+" | "-" )? [0-9]+ )? float_suffix?
integer ::= [0-9]+ int_suffix*
int_suffix ::= "l" | "L" | "ll" | "LL" | "u" | "U"
float_suffix ::= "l" | "L" | "f" | "F"
/* ---- Character classes ---- */
octal_digit ::= [0-7]
hex_digit ::= [0-9a-fA-F]
char ::= [^"\]