nomsu/nomsu.peg

file (File):
    {| shebang?
        (ignored_line %nl)*
        statement (nodent statement)*
        (%nl ignored_line)*
    (!. / (("" -> "Parse error") => error)?) |}

shebang: "#!" [^%nl]* %nl

statement: functioncall / expression
noeol_statement: noeol_functioncall / noeol_expression
inline_statement: inline_functioncall / inline_expression

inline_thunk (Thunk): {| ":" %ws* inline_statement |}
eol_thunk (Thunk): {| ":" %ws* noeol_statement eol |}
indented_thunk (Thunk):
    {| ":" indent
            statement (nodent statement)*
        (dedent / (("" -> "Error while parsing thunk") => error))
    |}

inline_nomsu (Nomsu): "\" inline_expression
eol_nomsu (Nomsu): "\" noeol_expression
indented_nomsu (Nomsu): "\" expression

inline_expression:
    number / variable / inline_string / inline_list / inline_dict / inline_nomsu
    / ("(" %ws* (inline_thunk / inline_statement) %ws* ")")
noeol_expression:
    indented_string / indented_nomsu / indented_list / indented_dict / indented_thunk
    / ("(..)" indent
        statement
    (dedent / (("" -> "Error while parsing indented expression") => error))
    ) / inline_expression
expression: eol_thunk / eol_nomsu / noeol_expression

-- Function calls need at least one word in them
inline_functioncall (FunctionCall):
    {| (inline_expression %ws*)* word (%ws* (inline_expression / word))* (%ws* inline_thunk)?|}
noeol_functioncall (FunctionCall):
    {| (noeol_expression %ws*)* word (%ws* (noeol_expression / word))* |}
functioncall (FunctionCall):
    {| (expression (dotdot / %ws*))* word ((dotdot / %ws*) (expression / word))* |}

word (Word): { %operator / (!number plain_word) }

inline_string (String):
    '"' {|
        ({~ (('\"' -> '"') / ('\\' -> '\') / ('\..' -> '..') / %escape_char / [^%nl\"])+ ~}
        / string_interpolation)*
    |} '"'
indented_string (String):
    '".."' %ws* line_comment? %nl %gt_nodented? {|
        ({~
            (("\\" -> "\") / (("\" eol %nl %gt_nodented "..") -> "")
            / (%nl+ {~ %gt_nodented -> "" ~}) / [^%nl\])+
        ~} / string_interpolation)*
    |} ((!.) / (&(%nl+ !%gt_nodented)) / (("" -> "Error while parsing String") => error))
string_interpolation:
    "\" (variable / inline_list / inline_dict / inline_string / ("(" %ws* (inline_thunk / inline_statement) %ws* ")"))

number (Number): (("-"? (([0-9]+ "." [0-9]+) / ("." [0-9]+) / ([0-9]+)))-> tonumber)

-- Variables can be nameless (i.e. just %) and can't contain operators like apostrophe
-- which is a hack to allow %'s to parse as "%" and "' s" separately
variable (Var): "%" { plain_word? }

inline_list (List):
    "[" %ws* {| (inline_list_item (comma inline_list_item)* comma?)? |} %ws* "]"
indented_list (List):
    "[..]" indent {|
        list_line (nodent list_line)*
    |}
    (dedent / (("" -> "Error while parsing list") => error))
list_line:
    (inline_list_item (comma inline_list_item)* (comma (functioncall / expression)?)?)
    / (functioncall / expression)
inline_list_item: inline_functioncall / inline_expression

inline_dict (Dict):
    "{" %ws* {| (inline_dict_item (comma inline_dict_item)* comma?)? |} %ws* "}"
indented_dict (Dict):
    "{..}" indent {|
        dict_line (nodent dict_line)*
    |}
    (dedent / (("" -> "Error while parsing dict") => error))
dict_line:
    (inline_dict_item (comma inline_dict_item)* (comma (functioncall / expression)?)?)
    / {| {:dict_key: inline_expression / word :} %ws* "=" %ws* {:dict_value: functioncall / expression :} |}
inline_dict_item:
    {| {:dict_key: inline_expression / word :} %ws* "=" %ws* {:dict_value: inline_functioncall / inline_expression :} |}

block_comment: "#.." [^%nl]* (%nl (%ws* &%nl))* %nl %indented [^%nl]+ (%nl ((%ws* ((!.) / &%nl)) / (!%dedented [^%nl]+)))*
line_comment: "#" [^%nl]*

eol: %ws* line_comment? (!. / &%nl)
ignored_line: (%nodented (block_comment / line_comment)) / (%ws* (!. / &%nl))
indent: eol (%nl ignored_line)* %nl %indented ((block_comment/line_comment) (%nl ignored_line)* nodent)?
nodent: eol (%nl ignored_line)* %nl %nodented
dedent: eol (%nl ignored_line)* (((!.) &%dedented) / (&(%nl %dedented)))
comma: %ws* "," %ws*
dotdot: nodent ".." %ws*
plain_word: ([a-zA-Z0-9_] / %utf8_char)+