Axon Grammar

Legend

Legend for BNF Grammar:

:=      is defined as
<x>     non-terminal
"x"     literal
'x'     char literal
[x]     optional
(x)     grouping
s-e     inclusive char range
x*      zero or more times
x+      one or more times
x|x     or

Productions

<topFunc>      :=  <lambda-n> | <defcomp>
<defcomp>      :=  "defcomp" <cells> [<do>] "end"
<cells>        :=  [<cell> <nl>]*
<cell>         :=  <id> <dict>

<expr>         :=  <lambda> | <def> | <if> | <list> | <dict> | <do> |
                   <return> | <throw> | <tryCatch> | <defcomp> |
                   <assignExpr>

<do>           :=  "do" <exprs> "end"
<exprs>        :=  <expr> (<exprSep> <expr>)*
<exprSep>      :=  ";" | <nl>

<var>          :=  <qname>
<qname>        :=  [<id> "::" ] <id>

<list>         :=  "[" <listItems> "]"
<listItems>    :=  [ <expr> ("," <expr>)* [","] ]

<dict>         :=  "{" <dictItems> "}"
<dictItems>    :=  [ <dictItem> ("," <dictItem>)* [","] ]
<dictItem>     :=  <dictVal> | <dictMarker> | <dictRemove>
<dictVal>      :=  <idOrKeyword> ":" <expr>
<dictMarker>   :=  <idOrKeyword>
<dictRemove>   :=  "-" <idOrKeyword>

<lambda>       :=  <lambda-1> | <lambda-n>
<lambda-1>     :=  <id> "=>" <expr>
<lambda-n>     :=  "(" <params> ")" "=>" <expr>
<params>       :=  [<param> ("," <param>)*]
<param>        :=  <id> [":" <expr>]

<def>          :=  <id> ":" <expr>

<if>           :=  "if" "(" <expr> ")" <expr> ["else" <expr>]

<return>       :=  "return" <expr>

<throw>        :=  "throw" <expr>
<tryCatch>     :=  "try" <expr> "catch" ["(" <id> ")"] <expr>

<defcomp>      :=  "compdef [<compcell>] [<do>] "end"
<compcell>     :=  <id> ":" <dict>

<assignExpr>   :=  <condOrExpr> ("=" <assignExpr>)
<condOrExpr>   :=  <condAndExpr> ("and" <condAndExpr>)*
<condAndExpr>  :=  <compareExpr> ("or" <compareExpr>)*
<compareExpr>  :=  <rangeExpr> (("==" | "!=" | "<" | "<=" |
                   ">=" | ">" | "<=>") <rangeExpr>)*
<rangeExpr>    :=  <addExpr> ".." <addExpr>
<addExpr>      :=  <multExpr> (("+" | "-") <multExpr>)*
<multExpr>     :=  <unaryExpr> (("*" | "/") <unaryExpr>)*
<unaryExpr>    :=  ("-" | "not") <termExpr>
<termExpr>     :=  <termBase> <termChain>*
<termBase>     :=  <var> | <groupedExpr> | <literal> | <typeRef>
<groupedExpr>  :=  "(" <expr> ")"

<termChain>    :=  <call> | <dotCall> | <index> | <trapCall>
<call>         :=  "(" [<callArg> ("," <callArg>)*] [<lambda>]
<callArg>      :=  <expr> | "_"
<dotCall>      :=  "." [<nl>] <qname> [<call> | <lamdba-1>]
<index>        :=  "[" <expr> "]"
<trapCall>     :=  "->" <id>

<typeRef>      :=  [<typeLibName> "::"] <typename>
<typeLibName>  :=  <id> ("." <id>)*

<literal>      :=  <null> | <bool> | <number> | <str> | <date> |
                   <time> | <month> | <recId>

<idOrKeyword>  :=  <id> | <keyword>

<keyword>      :=  "and" | "catch" | "defcomp" | "deflinks" | "do" | "else" |
                   "end" | "false" | "if" | "not" | "null" | "or" | "return" |
                   "throw" | "true" | "try"

Tokens

<bool>      :=  "true" | "false"
<null>      :=  "null"
<id>        :=  <idFirst> (<idRest>)*
<idFirst>   :=  alphaLo
<idRest>    :=  alphaLo | alphaHi | digit | '_'
<typename>  :=  <alphaHi> (<idRest>)*
<alphaLo>   :=  ('a' - 'z')
<alphaHi>   :=  ('Z' - 'Z')
<digit>     :=  ('0' - '9')
<digits>    :=  <digit> (<digit> | "_")*
<number>    :=  <hex> | <decimal>
<hex>       :=  "0x" <hexDigit> (<hexDigit> | "_")*
<hexDigit>  :=  ('a'-'f') | ('A'-'F') | digit
<decimal>   :=  ["-"] <digits> ["." <digits>] [<exp>] [<unit>]
<exp>       :=  "e"|"E" ["+"|"-"] <digits>
<unit>      :=  <unitChar>*
<unitChar>  :=  <alpha> | "%" | "_" | "/" | "$" | any char > 128  // see sys::Unit
<str>       :=  see Fantom grammar (single line single quote, and multi-line triple quote)
<date>      :=  yyyy-mm-dd
<time>      :=  [h]h:mm[:ss[.fff]]  // hour and secs optional
<month>     :=  yyyy-mm
<ref>       :=  "@" refChar (refChar)*
<symbol>    :=  "^" refChar (refChar)*
<refChar>   :=  <alpha> | <digit> | '_' | ':' | '.' | '~' | '-'
<nl>        :=  newline "\n"