grammar-examples

gistfile1.txt

(let grammar (grammar<- "
shifts:    shift* :end.
shift:     start [nap* :list] :list.
start:     timestamp :drop 'Guard #' :count ' begins shift\n'.

nap:       timestamp 'falls asleep\n'
           timestamp 'wakes up\n'    :list.

timestamp: '[' date _ time ']' _.
date:      (!_ 1)+.
time:      :count :drop ':' :count.

_:         :whitespace.
"))

(let grammar (grammar<- "
main: clause* :list '\n\n' program.  # N.B. no :end
clause: 'Before: [' [:count (', ' :count)^3 :list] ']\n'
        [:count (' ' :count)^3 :list] '\n'
        'After:  [' [:count (', ' :count)^3 :list] ']\n\n' :list.

program: insn* :list.
insn:    :count (' ' :count)^3 '\n' :list.
"))

(let grammar (grammar<- "
main: '^' e '$'.
e:    f**'|' :Alt.
f:    g*     :Seq.
g:    dir | '(' e ')'.
dir:  {'N' | 'S' | 'E' | 'W'} :Dir.
"))

(let grammar (grammar<- "
main: army**separator :end.
army: army_name ':\n' [group* :list] :list.
army_name: { (!':' 1)* }.
group: :count ' units each with ' :count ' hit points ' opt_qualities 
       'with an attack that does ' :count ' ' word 
       ' damage at initiative ' :count '\n' :Group.
opt_qualities: '(' qualities ') ' | :list.
qualities: quality_list++'; ' :list.
quality_list: {'weak'|'immune'} ' to ' [word++', ' :list] :list.
word: {:letter+}.
separator: '\n'.
"))

(let g (grammar<- "
rule: bag _ 'contain' _ [bags :list] '.' :end.
bag: {word _ word} _ ('bags'|'bag').
bags: 'no' _ 'other' _ 'bags' | [:count _ bag :list] ++ (','_).
word: :letter+.
_: :whitespace.
"))

(let g1 (grammar<- "
line: expr :end.
expr: factor (_ '*' _ factor :mul | _ '+' _ factor :add)*.
factor: :integer | '(' expr ')'.
_: :whitespace.
"))
(let g2 (grammar<- "
line: expr :end.
expr: e1 (_ '*' _ e1 :mul)*.
e1: factor (_ '+' _ factor :add)*.
factor: :integer | '(' expr ')'.
_: :whitespace.
"))

(let g1 (grammar<- "
start: main :end.
main: :count ': ' rhs.
rhs: '\"' {1} '\"' :Lit | alt.
alt: seq ('|'_ alt :Alt)?.
seq: :count :Ref _ (seq :Seq)?.
_: :whitespace*.
"))

(let grammar (grammar<- "
regex    :  exp :end.
exp      :  term ('|' exp     :either)*
         |                    :empty.
term     :  factor (term      :then)*.
factor   :  primary (  '*'    :star
                     | '+'    :plus
                     | '?'    :maybe
                    )?.
primary  :  '(' exp ')'
         |  '[' rune* ']'     :join :oneof
         |  '.'               :dot
         |  '\\\\' {1}        :literal
         |  !( '.' | '(' | ')'
             | '*' | '+' | '?'
             | '|' | '[' | ']')
            {1}               :literal.
rune     :  '\\\\' {1}
         |  !']' {1}.
"))

(let junk "
main: r*.
r: .
s: 'hey' r.
")
(let bal "
bal  :  ('(' bal ')' bal)?.
")
(let balanced "
bal  :  '(' c* ')'.
c    :  !('(' | ')') :anyone
     |  bal.
")
(let a-and-b-equal-counts "
start :  S :end.
S     :  'a' B
      |  'b' A
      |  .

A     :  'a' S
      |  'b' A A.

B     :  'b' S
      |  'a' B B.
")
(let text "
split  :  (p | chunk :join) split | .  # XXX why not a *?
chunk  :  p
       |  :anyone chunk.
p      :  :whitespace.
")