Language "OCaml Light"

Lexis SDF

// 1 Lexical conventions
  
// Comments

lexical syntax

  LAYOUT = LEX-block-comment
  LEX-block-comment = "(*" LEX-comment-part* "*)" 
  
  LEX-comment-part = ~[\(\)\*]
  LEX-comment-part = LEX-asterisk
  LEX-comment-part = LEX-left-paren
  LEX-comment-part = LEX-right-paren
  LEX-comment-part = LEX-block-comment
  
  LEX-asterisk    = [\*]
  LEX-left-paren  = [\(] 
  LEX-right-paren = [\)]
 
lexical restrictions

  LEX-asterisk   -/- [\)]
  LEX-left-paren -/- [\*]

context-free restrictions

  LAYOUT? -/- [\(].[\*]

// Identifiers

lexical syntax
       
  ident =             keyword    {reject}
  lowercase-ident =   keyword    {reject}
  
lexical restrictions

  ident 
  lowercase-ident 
  capitalized-ident -/- [A-Za-z0-9\_\']
Syntax SDF

// Integer literals

context-free restrictions

  integer-literal     -/- [0-9eE]
Syntax SDF

// Floating-point literals

context-free restrictions

  float-literal       -/- [0-9eE]

// String literals

syntax

  string-character-star ::= string-character _ string-character-star    {avoid}
Lexis SDF

// Keywords

lexical restrictions

      "and"          "as"         "assert"   "asr"       "begin"     "class"
      "constraint"   "do"         "done"     "downto"    "else"      "end"
      "exception"    "external"   "false"    "for"       "fun"       "function"
      "functor"      "if"         "in"       "include"   "inherit"   "initializer"
      "land"         "lazy"       "let"      "lor"       "lsl"       "lsr"
      "lxor"         "match"      "method"   "mod"       "module"    "mutable" 
      "new"          "nonrec"     "object"   "of"        "open"      "or"     
      "private"      "rec"        "sig"      "struct"    "then"      "to"
      "true"         "try"        "type"     "val"       "virtual"   "when" 
      "while"        "with"
  -/- [A-Za-z0-9\_] 

// Key symbols

infix-op-1 infix-op-2 infix-op-3 infix-op-4 
infix-op-5 infix-op-6 infix-op-7 infix-op-8 
       -/- [\!\$\%\&\*\+\-\.\/\:\<\=\>\?\@\^\|\~]
  "["  -/- [\|]
  "|"  -/- [\]]
  ":"  -/- [\:]
  ";"  -/- [\;]

lexical syntax

  infix-op-3 = "->" {reject}

  infix-op-5 = "<-" {reject}
Syntax SDF


// 4 Type expressions

context-free syntax

typexpr ::= typexpr '->' typexpr    {right}
typexpr ::= typexpr star-typexpr+   {non-assoc}

context-free priorities

typexpr ::= typexpr typeconstr  
>
constr-args ::= typexpr star-typexpr*
>
typexpr ::= typexpr star-typexpr+
>
typexpr ::= typexpr '->' typexpr

context-free priorities

star-typexpr ::= '*' typexpr
>
typexpr ::= typexpr star-typexpr+


// 6 Patterns

context-free syntax

pattern ::= pattern '|' pattern    {left}
pattern ::= pattern comma-pattern+ {non-assoc}
pattern ::= pattern '::' pattern   {right}

context-free priorities

pattern ::= constr pattern
>
pattern ::= pattern '::' pattern
>
pattern ::= pattern comma-pattern+
>
pattern ::= pattern '|' pattern
>
pattern ::= pattern 'as' value-name

context-free priorities
{
comma-pattern ::= ',' pattern
(pattern comma-pattern*)
} >
pattern ::= pattern comma-pattern+


// 7 Expressions      

context-free syntax
  
expr ::= expr argument+          {non-assoc,avoid}
expr ::= '-' expr                {avoid}
expr ::= expr infix-op-1 expr    {right}
expr ::= expr infix-op-2 expr    {left}
expr ::= expr infix-op-3 expr    {left,prefer}
expr ::= expr '::' expr          {right}
expr ::= expr infix-op-4 expr    {right}
expr ::= expr infix-op-5 expr    {left}
expr ::= expr infix-op-6 expr    {right}
expr ::= expr infix-op-7 expr    {right}
expr ::= expr comma-expr+        {non-assoc}
expr ::= expr infix-op-8 expr    {right}
expr ::= expr '.' field '<-' expr{right}
expr ::= expr '.(' expr ')' '<-' expr{right}
expr ::= expr ';' expr           {right}

context-free priorities

argument ::= expr
>
expr ::= prefix-symbol expr
>
expr ::= expr '.' field
> {
expr ::= expr argument+
expr ::= 'assert' expr
} > {
expr ::= '-' expr
expr ::= '-.' expr
} > 
expr ::= expr infix-op-1 expr
> 
expr ::= expr infix-op-2 expr
> 
expr ::= expr infix-op-3 expr
> 
expr ::= expr '::' expr
> 
expr ::= expr infix-op-4 expr
> 
expr ::= expr infix-op-5 expr
> 
expr ::= expr infix-op-6 expr
>
expr ::= expr infix-op-7 expr
> 
expr ::= expr comma-expr+
> {
expr ::= expr '.' field '<-' expr
expr ::= expr '.(' expr ')' '<-' expr
expr ::= expr infix-op-8 expr
} > 
expr ::= expr ';' expr

context-free priorities

expr ::= prefix-symbol expr
>
expr ::= expr '.(' expr ')'
<0> >
expr ::= expr argument+

context-free priorities
{
argument ::= expr
expr ::= expr '.' field
expr ::= expr '.(' expr ')'
expr ::= expr argument+
expr ::= 'assert' expr
expr ::= expr infix-op-1 expr
expr ::= expr infix-op-2 expr
expr ::= expr infix-op-3 expr
expr ::= expr '::' expr
expr ::= expr infix-op-4 expr
expr ::= expr infix-op-5 expr
expr ::= expr infix-op-6 expr
expr ::= expr infix-op-7 expr
expr ::= expr comma-expr+
expr ::= expr '.' field '<-' expr
expr ::= expr '.(' expr ')' '<-' expr
expr ::= expr infix-op-8 expr
expr ::= expr ';' expr
} <0>. > {
expr ::= 'if' expr 'then' expr ('else' expr)?
expr ::= 'match' expr 'with' pattern-matching
expr ::= 'function' pattern-matching
expr ::= 'fun' pattern+ '->' expr
expr ::= 'try' expr 'with' pattern-matching
expr ::= let-definition 'in' expr
}

context-free priorities
{
comma-expr ::= ',' expr
(expr comma-expr*)
} > 
expr ::= expr comma-expr+

context-free priorities
{
expr ::= '[' expr semic-expr* ']'
expr ::= '[' expr semic-expr* ';' ']'
expr ::= '[|' expr semic-expr* '|]'
expr ::= '[|' expr semic-expr* ';' '|]'
semic-expr ::= ';' expr
(expr semic-expr*)
expr ::= '{' field '=' expr semic-field-expr* '}'
expr ::= '{' field '=' expr semic-field-expr* ';' '}'
expr ::= '{' expr 'with' field '=' expr semic-field-expr* '}'
expr ::= '{' expr 'with' field '=' expr semic-field-expr* ';' '}'
semic-field-expr ::= ';' field '=' expr
} > 
expr ::= expr ';' expr