Add canonical grammar and CodeMirror playground

2026-07-08 23:41:26 +09:00
parent a07f4c48aa
commit ee031bd2e8
15 changed files with 709 additions and 81 deletions
@@ -0,0 +1,172 @@
+@top Source { Statement* }
+
+Statement {
+  FieldDefinition semicolon? |
+  Expression semicolon?
+}
+
+Expression { DefaultExpression }
+
+DefaultExpression {
+  PatchExpression |
+  PatchExpression !default default DefaultExpression
+}
+
+PatchExpression {
+  ComposeExpression |
+  PatchExpression !patch slashSlash ComposeExpression
+}
+
+ComposeExpression {
+  LogicalOrExpression |
+  ComposeExpression !compose amp LogicalOrExpression
+}
+
+LogicalOrExpression {
+  LogicalAndExpression |
+  LogicalOrExpression !or pipePipe LogicalAndExpression
+}
+
+LogicalAndExpression {
+  ComparisonExpression |
+  LogicalAndExpression !and ampAmp ComparisonExpression
+}
+
+ComparisonExpression {
+  ConcatExpression |
+  ConcatExpression !compare CompareOperator ConcatExpression
+}
+
+ConcatExpression {
+  AdditiveExpression |
+  ConcatExpression !concat plusPlus AdditiveExpression
+}
+
+AdditiveExpression {
+  MultiplicativeExpression |
+  AdditiveExpression !add (plus | minus) MultiplicativeExpression
+}
+
+MultiplicativeExpression {
+  UnaryExpression |
+  MultiplicativeExpression !multiply (star | slash) UnaryExpression
+}
+
+UnaryExpression {
+  PostfixExpression |
+  (bang | minus) !unary UnaryExpression
+}
+
+PostfixExpression {
+  PrimaryExpression |
+  PostfixExpression !call CallSuffix |
+  PostfixExpression !path dot identifier
+}
+
+CallSuffix { lParen ArgumentList? rParen }
+ArgumentList { Expression (comma Expression)* comma? }
+
+PrimaryExpression {
+  Literal |
+  identifier |
+  ComparisonConstraint |
+  Object |
+  Array |
+  LetExpression |
+  FunctionExpression |
+  MatchExpression |
+  ImportExpression |
+  lParen Expression rParen
+}
+
+Literal { string | integer | float | true | false | regex }
+CompareOperator { equalEqual | bangEqual | lt | lte | gt | gte }
+ComparisonConstraint { (lt | lte | gt | gte) Expression }
+
+Object { lBrace (FieldDefinition (semicolon FieldDefinition)* semicolon?)? rBrace }
+FieldDefinition { FieldPath equal Expression }
+FieldPath { identifier !fieldPath (dot identifier)* }
+
+Array { lBracket (Expression (comma Expression)* comma?)? rBracket }
+
+LetExpression { let FieldDefinitionList in Expression }
+FieldDefinitionList { (FieldDefinition semicolon)* }
+
+FunctionExpression { lParen ParameterList? rParen arrow Expression }
+ParameterList { Parameter (comma Parameter)* comma? }
+Parameter { identifier colon Expression }
+
+MatchExpression { match Expression lBrace (MatchArm (semicolon MatchArm)* semicolon?)? rBrace }
+MatchArm { Pattern colon Expression }
+Pattern { underscore | Expression }
+
+ImportExpression { import string }
+
+@precedence {
+  fieldPath @left,
+  default @right,
+  patch @left,
+  compose @left,
+  or @left,
+  and @left,
+  compare @left,
+  concat @left,
+  add @left,
+  multiply @left,
+  unary,
+  call @left,
+  path @left
+}
+
+@tokens {
+  let { "let" }
+  in { "in" }
+  match { "match" }
+  import { "import" }
+  default { "default" }
+  true { "true" }
+  false { "false" }
+
+  identifier { $[A-Za-z_] $[A-Za-z0-9_]* }
+  integer { $[0-9]+ }
+  float { $[0-9]+ "." $[0-9]+ }
+  string { '"' (!["\\\n] | "\\" _)* '"' }
+  regex { "/" (![/\\\n] | "\\" _)+ "/" }
+  comment { "#" ![\n]* }
+
+  lBrace { "{" }
+  rBrace { "}" }
+  lBracket { "[" }
+  rBracket { "]" }
+  lParen { "(" }
+  rParen { ")" }
+  semicolon { ";" }
+  comma { "," }
+  dot { "." }
+  colon { ":" }
+  equal { "=" }
+  equalEqual { "==" }
+  bang { "!" }
+  bangEqual { "!=" }
+  arrow { "=>" }
+  amp { "&" }
+  ampAmp { "&&" }
+  pipePipe { "||" }
+  plus { "+" }
+  plusPlus { "++" }
+  minus { "-" }
+  star { "*" }
+  slash { "/" }
+  slashSlash { "//" }
+  gt { ">" }
+  gte { ">=" }
+  lt { "<" }
+  lte { "<=" }
+  underscore { "_" }
+
+  whitespace { @whitespace+ }
+
+  @precedence { let, in, match, import, default, true, false, float, integer, underscore, identifier }
+}
+
+@skip { whitespace | comment }