Implement parsing of partials syntax

pkg/composableschemadsl/dslshape/dslshape.go

@@ -37,6 +37,8 @@ const (
 	NodeTypeCaveatTypeReference // A type reference for a caveat parameter.
 
 	NodeTypeImport
+	NodeTypePartial
+	NodeTypePartialReference // A location where a partial is referenced
 )
 
 const (
@@ -195,4 +197,14 @@ const (
 	// NodeTypeImport
 	//
 	NodeImportPredicatePath = "import-path"
+
+	//
+	// NodeTypePartial
+	//
+	NodePartialPredicateName = "partial-name"
+
+	//
+	// NodeTypePartialReference
+	//
+	NodePartialReferencePredicateName = "partial-reference-name"
 )

pkg/composableschemadsl/lexer/lex_def.go

@@ -81,6 +81,7 @@ var keywords = map[string]struct{}{
 	"import":     {},
 	"all":        {},
 	"any":        {},
+	"partial":    {},
 }
 
 // IsKeyword returns whether the specified input string is a reserved keyword.

pkg/composableschemadsl/lexer/lex_test.go

@@ -65,6 +65,7 @@ var lexerTests = []lexerTest{
 	{"keyword", "import", []Lexeme{{TokenTypeKeyword, 0, "import", ""}, tEOF}},
 	{"keyword", "all", []Lexeme{{TokenTypeKeyword, 0, "all", ""}, tEOF}},
 	{"keyword", "nil", []Lexeme{{TokenTypeKeyword, 0, "nil", ""}, tEOF}},
+	{"keyword", "partial", []Lexeme{{TokenTypeKeyword, 0, "partial", ""}, tEOF}},
 	{"identifier", "define", []Lexeme{{TokenTypeIdentifier, 0, "define", ""}, tEOF}},
 	{"typepath", "foo/bar", []Lexeme{
 		{TokenTypeIdentifier, 0, "foo", ""},

pkg/composableschemadsl/parser/parser.go

@@ -65,6 +65,9 @@ Loop:
 		case p.isKeyword("import"):
 			rootNode.Connect(dslshape.NodePredicateChild, p.consumeImport())
 
+		case p.isKeyword("partial"):
+			rootNode.Connect(dslshape.NodePredicateChild, p.consumePartial())
+
 		default:
 			p.emitErrorf("Unexpected token at root level: %v", p.currentToken.Kind)
 			break Loop
@@ -264,10 +267,39 @@ func (p *sourceParser) consumeDefinition() AstNode {
 
 	defNode.MustDecorate(dslshape.NodeDefinitionPredicateName, definitionName)
 
+	p.consumeDefinitionOrPartialImpl(defNode)
+
+	return defNode
+}
+
+// consumePartial attempts to consume a single schema partial.
+// ```partial somepartial { ... }```
+func (p *sourceParser) consumePartial() AstNode {
+	partialNode := p.startNode(dslshape.NodeTypePartial)
+	defer p.mustFinishNode()
+
+	// partial ...
+	p.consumeKeyword("partial")
+	definitionName, ok := p.consumeTypePath()
+	if !ok {
+		return partialNode
+	}
+
+	partialNode.MustDecorate(dslshape.NodePartialPredicateName, definitionName)
+
+	p.consumeDefinitionOrPartialImpl(partialNode)
+
+	return partialNode
+}
+
+// consumeDefinitionOrPartialImpl does the work of parsing and consuming
+// the internals of a given definition or partial.
+// Definitions and partials have the same set of allowable internals.
+func (p *sourceParser) consumeDefinitionOrPartialImpl(node AstNode) AstNode {
 	// {
-	_, ok = p.consume(lexer.TokenTypeLeftBrace)
+	_, ok := p.consume(lexer.TokenTypeLeftBrace)
 	if !ok {
-		return defNode
+		return node
 	}
 
 	// Relations and permissions.
@@ -281,10 +313,13 @@ func (p *sourceParser) consumeDefinition() AstNode {
 		// permission ...
 		switch {
 		case p.isKeyword("relation"):
-			defNode.Connect(dslshape.NodePredicateChild, p.consumeRelation())
+			node.Connect(dslshape.NodePredicateChild, p.consumeRelation())
 
 		case p.isKeyword("permission"):
-			defNode.Connect(dslshape.NodePredicateChild, p.consumePermission())
+			node.Connect(dslshape.NodePredicateChild, p.consumePermission())
+
+		case p.isToken(lexer.TokenTypeEllipsis):
+			node.Connect(dslshape.NodePredicateChild, p.consumePartialReference())
 		}
 
 		ok := p.consumeStatementTerminator()
@@ -293,7 +328,7 @@ func (p *sourceParser) consumeDefinition() AstNode {
 		}
 	}
 
-	return defNode
+	return node
 }
 
 // consumeRelation consumes a relation.
@@ -597,6 +632,21 @@ func (p *sourceParser) tryConsumeNilExpression() (AstNode, bool) {
 	return node, true
 }
 
+func (p *sourceParser) consumePartialReference() AstNode {
+	partialReferenceNode := p.startNode(dslshape.NodeTypePartialReference)
+	defer p.mustFinishNode()
+
+	p.consume(lexer.TokenTypeEllipsis)
+	identifier, ok := p.consumeIdentifier()
+	if !ok {
+		return partialReferenceNode
+	}
+
+	partialReferenceNode.MustDecorate(dslshape.NodePartialReferencePredicateName, identifier)
+
+	return partialReferenceNode
+}
+
 func (p *sourceParser) consumeImport() AstNode {
 	importNode := p.startNode(dslshape.NodeTypeImport)
 	defer p.mustFinishNode()

pkg/composableschemadsl/parser/parser_test.go

@@ -128,6 +128,11 @@ func TestParser(t *testing.T) {
 		{"local imports with unterminated string on import test", "localimport_with_unterminated_string"},
 		{"local imports with mismatched quotes on import test", "localimport_with_mismatched_quotes"},
 		{"local imports with keyword in import path test", "localimport_import_path_with_keyword"},
+		{"top-level block with unrecognized keyword", "nonsense_top_level_block"},
+		{"partials happy path", "partials"},
+		{"partials with malformed partial reference", "partials_with_malformed_partial_reference"},
+		{"partials with malformed reference splat", "partials_with_malformed_reference_splat"},
+		{"partials with malformed partial block", "partials_with_malformed_partial_block"},
 	}
 
 	for _, test := range parserTests {

pkg/composableschemadsl/parser/tests/nonsense_top_level_block.zed

@@ -0,0 +1,4 @@
+nonsense thing {
+  relation: user
+  permission view = user
+}

pkg/composableschemadsl/parser/tests/nonsense_top_level_block.zed.expected

@@ -0,0 +1,11 @@
+NodeTypeFile
+  end-rune = -1
+  input-source = top-level block with unrecognized keyword
+  start-rune = 0
+  child-node =>
+    NodeTypeError
+      end-rune = -1
+      error-message = Unexpected token at root level: TokenTypeIdentifier
+      error-source = nonsense
+      input-source = top-level block with unrecognized keyword
+      start-rune = 0

pkg/composableschemadsl/parser/tests/partials.zed

@@ -0,0 +1,10 @@
+partial view_partial {
+  relation user: user
+  permission view = user
+}
+
+definition user {}
+
+definition resource {
+  ...view_partial
+}

pkg/composableschemadsl/parser/tests/partials.zed.expected

@@ -0,0 +1,54 @@
+NodeTypeFile
+  end-rune = 134
+  input-source = partials happy path
+  start-rune = 0
+  child-node =>
+    NodeTypePartial
+      end-rune = 70
+      input-source = partials happy path
+      partial-name = view_partial
+      start-rune = 0
+      child-node =>
+        NodeTypeRelation
+          end-rune = 43
+          input-source = partials happy path
+          relation-name = user
+          start-rune = 25
+          allowed-types =>
+            NodeTypeTypeReference
+              end-rune = 43
+              input-source = partials happy path
+              start-rune = 40
+              type-ref-type =>
+                NodeTypeSpecificTypeReference
+                  end-rune = 43
+                  input-source = partials happy path
+                  start-rune = 40
+                  type-name = user
+        NodeTypePermission
+          end-rune = 68
+          input-source = partials happy path
+          relation-name = view
+          start-rune = 47
+          compute-expression =>
+            NodeTypeIdentifier
+              end-rune = 68
+              identifier-value = user
+              input-source = partials happy path
+              start-rune = 65
+    NodeTypeDefinition
+      definition-name = user
+      end-rune = 90
+      input-source = partials happy path
+      start-rune = 73
+    NodeTypeDefinition
+      definition-name = resource
+      end-rune = 133
+      input-source = partials happy path
+      start-rune = 93
+      child-node =>
+        NodeTypePartialReference
+          end-rune = 131
+          input-source = partials happy path
+          partial-reference-name = view_partial
+          start-rune = 117

pkg/composableschemadsl/parser/tests/partials_with_malformed_partial_block.zed

@@ -0,0 +1,10 @@
+partial view_partial {
+  relation user: user
+  permission view = user
+
+
+definition user {}
+
+definition resource {
+  ...view_partial
+}

pkg/composableschemadsl/parser/tests/partials_with_malformed_partial_block.zed.expected

@@ -0,0 +1,60 @@
+NodeTypeFile
+  end-rune = 133
+  input-source = partials with malformed partial block
+  start-rune = 0
+  child-node =>
+    NodeTypePartial
+      end-rune = 69
+      input-source = partials with malformed partial block
+      partial-name = view_partial
+      start-rune = 0
+      child-node =>
+        NodeTypeRelation
+          end-rune = 43
+          input-source = partials with malformed partial block
+          relation-name = user
+          start-rune = 25
+          allowed-types =>
+            NodeTypeTypeReference
+              end-rune = 43
+              input-source = partials with malformed partial block
+              start-rune = 40
+              type-ref-type =>
+                NodeTypeSpecificTypeReference
+                  end-rune = 43
+                  input-source = partials with malformed partial block
+                  start-rune = 40
+                  type-name = user
+        NodeTypePermission
+          end-rune = 68
+          input-source = partials with malformed partial block
+          relation-name = view
+          start-rune = 47
+          compute-expression =>
+            NodeTypeIdentifier
+              end-rune = 68
+              identifier-value = user
+              input-source = partials with malformed partial block
+              start-rune = 65
+        NodeTypeError
+          end-rune = 69
+          error-message = Expected end of statement or definition, found: TokenTypeKeyword
+          error-source = definition
+          input-source = partials with malformed partial block
+          start-rune = 72
+    NodeTypeDefinition
+      definition-name = user
+      end-rune = 89
+      input-source = partials with malformed partial block
+      start-rune = 72
+    NodeTypeDefinition
+      definition-name = resource
+      end-rune = 132
+      input-source = partials with malformed partial block
+      start-rune = 92
+      child-node =>
+        NodeTypePartialReference
+          end-rune = 130
+          input-source = partials with malformed partial block
+          partial-reference-name = view_partial
+          start-rune = 116

pkg/composableschemadsl/parser/tests/partials_with_malformed_partial_reference.zed

@@ -0,0 +1,10 @@
+partial view_partial {
+  relation user: user
+  permission view = user
+}
+
+definition user {}
+
+definition resource {
+  ...view_partial and_something_else
+}