Implement support for optional token and rule getters

Fixes tunnelvisionlabs#265
sharwell · Jan 4, 2017 · 333aac5 · 333aac5
1 parent 16c8054
commit 333aac5
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Showing 4 changed files with 38 additions and 12 deletions.
diff --git a/reference/antlr4 b/reference/antlr4
diff --git a/src/ParserRuleContext.ts b/src/ParserRuleContext.ts
@@ -197,6 +197,19 @@ export class ParserRuleContext extends RuleContext {
 			return this.children[i];
 		}
 
+		let result = this.tryGetChild(i, ctxType);
+		if (result === undefined) {
+			throw new Error("The specified node does not exist");
+		}
+
+		return result;
+	}
+
+	tryGetChild<T extends ParseTree>(i: number, ctxType: { new (...args: any[]): T; }): T | undefined {
+		if (!this.children || i < 0 || i >= this.children.length) {
+			return undefined;
+		}
+
 		let j: number = -1; // what node with ctxType have we found?
 		for (let o of this.children) {
 			if (o instanceof ctxType) {
@@ -207,14 +220,23 @@ export class ParserRuleContext extends RuleContext {
 			}
 		}
 
-		throw new Error("The specified node does not exist");
+		return undefined;
 	}
 
 	getToken(ttype: number, i: number): TerminalNode {
-		if (!this.children || i < 0 || i >= this.children.length) {
+		let result = this.tryGetToken(ttype, i);
+		if (result === undefined) {
 			throw new Error("The specified token does not exist");
 		}
 
+		return result;
+	}
+
+	tryGetToken(ttype: number, i: number): TerminalNode | undefined {
+		if (!this.children || i < 0 || i >= this.children.length) {
+			return undefined;
+		}
+
 		let j: number = -1; // what token with ttype have we found?
 		for (let o of this.children) {
 			if (o instanceof TerminalNode) {
@@ -228,7 +250,7 @@ export class ParserRuleContext extends RuleContext {
 			}
 		}
 
-		throw new Error("The specified token does not exist");
+		return undefined;
 	}
 
 	getTokens(ttype: number): TerminalNode[] {
@@ -265,6 +287,10 @@ export class ParserRuleContext extends RuleContext {
 		throw new Error("Required ctxType was not provided");
 	}
 
+	tryGetRuleContext<T extends ParserRuleContext>(i: number, ctxType: { new (...args: any[]): T; }): T | undefined {
+		return this.tryGetChild(i, ctxType);
+	}
+
 	getRuleContexts<T extends ParserRuleContext>(ctxType: { new (...args: any[]): T; }): T[] {
 		let contexts: T[] = [];
 		if (!this.children) {

diff --git a/tool/pom.xml b/tool/pom.xml
@@ -85,13 +85,13 @@ Licensed under the BSD-3-Clause license. See LICENSE file in the project root fo
         <dependency>
             <groupId>com.tunnelvisionlabs</groupId>
             <artifactId>antlr4</artifactId>
-            <version>4.6.0.1</version>
+            <version>4.6.1-SNAPSHOT</version>
             <scope>compile</scope>
         </dependency>
         <dependency>
             <groupId>com.tunnelvisionlabs</groupId>
             <artifactId>antlr4-runtime</artifactId>
-            <version>4.6.0.1</version>
+            <version>4.6.1-SNAPSHOT</version>
             <scope>compile</scope>
         </dependency>
         <dependency>
@@ -223,7 +223,7 @@ Licensed under the BSD-3-Clause license. See LICENSE file in the project root fo
             <plugin>
                 <groupId>com.tunnelvisionlabs</groupId>
                 <artifactId>antlr4-testgen-maven-plugin</artifactId>
-                <version>4.6.0.1</version>
+                <version>4.6.1-SNAPSHOT</version>
                 <executions>
                     <execution>
                         <goals>

diff --git a/tool/resources/org/antlr/v4/tool/templates/codegen/TypeScript/TypeScript.stg b/tool/resources/org/antlr/v4/tool/templates/codegen/TypeScript/TypeScript.stg
@@ -699,8 +699,8 @@ TokenListDecl(t) ::= "_<t.name>: Token[] = []"
 RuleContextDecl(r) ::= "_<r.name>: <r.ctxName>"
 RuleContextListDecl(rdecl) ::= "_<rdecl.name>: <rdecl.ctxName>[] = []"
 
-ContextTokenGetterDecl(t)      ::=
-    "public <t.name>(): TerminalNode { return this.getToken(<parser.name>.<t.name>, 0); }"
+ContextTokenGetterDecl(t, optional)      ::=
+	"public <t.name>(): TerminalNode<if(optional)> | undefined<endif> { return this.<if(optional)>tryG<else>g<endif>etToken(<parser.name>.<t.name>, 0); }"
 ContextTokenListGetterDecl(t)  ::=
     "public <t.name>(): TerminalNode[];"
 ContextTokenListIndexedGetterDecl(t)  ::= <<
@@ -713,9 +713,9 @@ public <t.name>(i?: number): TerminalNode | TerminalNode[] {
 	}
 }
 >>
-ContextRuleGetterDecl(r)       ::= <<
-public <r.name>(): <r.ctxName> {
-	return this.getRuleContext(0, <r.ctxName>);
+ContextRuleGetterDecl(r, optional)       ::= <<
+public <r.name>(): <r.ctxName><if(optional)> | undefined<endif> {
+	return this.<if(optional)>tryG<else>g<endif>etRuleContext(0, <r.ctxName>);
 }
 >>
 ContextRuleListGetterDecl(r)   ::= <<