Add a pretty printer for Skylark ASTs
This can be used to canonically compare ASTs for equality, e.g. in tests.
RELNOTES: None
PiperOrigin-RevId: 160283160
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/ASTNode.java b/src/main/java/com/google/devtools/build/lib/syntax/ASTNode.java
index d2e22d9..18258a2 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/ASTNode.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/ASTNode.java
@@ -16,8 +16,9 @@
import com.google.common.annotations.VisibleForTesting;
import com.google.devtools.build.lib.events.Location;
-
+import java.io.IOException;
import java.io.Serializable;
+import java.util.List;
/**
* Root class for nodes in the Abstract Syntax Tree of the Build language.
@@ -73,12 +74,83 @@
return node;
}
+ /** Number of spaces that each indentation level expands to when pretty-printing. */
+ public static final int INDENT_WIDTH = 2;
+
+ /** Writes out the indentation prefix for a line. */
+ protected void printIndent(Appendable buffer, int indentLevel) throws IOException {
+ for (int i = 0; i < indentLevel * INDENT_WIDTH; i++) {
+ buffer.append(' ');
+ }
+ }
+
/**
- * Print the syntax node in a form useful for debugging. The output is not
- * precisely specified, and should not be used by pretty-printing routines.
+ * Writes out a suite of statements. The statements are indented one more level than given, i.e.,
+ * the {@code indentLevel} parameter should be the same as the parent node's.
+ *
+ * <p>This also prints out a {@code pass} line if the suite is empty.
+ */
+ protected void printSuite(Appendable buffer, List<Statement> statements, int parentIndentLevel)
+ throws IOException {
+ if (statements.isEmpty()) {
+ printIndent(buffer, parentIndentLevel + 1);
+ buffer.append("pass\n");
+ } else {
+ for (Statement stmt : statements) {
+ stmt.prettyPrint(buffer, parentIndentLevel + 1);
+ }
+ }
+ }
+
+ /**
+ * Writes a pretty-printed representation of this node to a buffer, assuming the given starting
+ * indentation level.
+ *
+ * <p>For expressions, the indentation level is ignored. For statements, the indentation is
+ * written, then the statement contents (which may include multiple lines with their own
+ * indentation), then a newline character.
+ *
+ * <p>Indentation expands to {@code INDENT_WIDTH} many spaces per indent.
+ *
+ * <p>Pretty printing returns the canonical source code corresponding to an AST. Generally, the
+ * output can be round-tripped: Pretty printing an AST and then parsing the result should give you
+ * back an equivalent AST.
+ *
+ * <p>Pretty printing can also be used as a proxy for comparing for equality between two ASTs.
+ * This can be very useful in tests. However, it is still possible for two different trees to have
+ * the same pretty printing. In particular, {@link BuildFileAST} includes import metadata and
+ * comment information that is not reflected in the string.
+ */
+ public abstract void prettyPrint(Appendable buffer, int indentLevel) throws IOException;
+
+ /** Same as {@link #prettyPrint(Appendable, int)}, except with no indent. */
+ public void prettyPrint(Appendable buffer) throws IOException {
+ prettyPrint(buffer, 0);
+ }
+
+ /** Returns a pretty-printed representation of this node. */
+ public String prettyPrint() {
+ StringBuilder builder = new StringBuilder();
+ try {
+ prettyPrint(builder);
+ } catch (IOException e) {
+ // Not possible for StringBuilder.
+ throw new AssertionError(e);
+ }
+ return builder.toString();
+ }
+
+ /**
+ * Print the syntax node in a form useful for debugging.
+ *
+ * <p>The output is not precisely specified; use {@link #prettyPrint()} if you need more stable
+ * and complete information. For instance, this function may omit child statements of compound
+ * statements, or parentheses around some expressions. It may also abbreviate large list literals.
*/
@Override
- public abstract String toString();
+ public String toString() {
+ return prettyPrint();
+ }
@Override
public int hashCode() {
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/AbstractComprehension.java b/src/main/java/com/google/devtools/build/lib/syntax/AbstractComprehension.java
index deb939e..12adf1a 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/AbstractComprehension.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/AbstractComprehension.java
@@ -16,6 +16,7 @@
import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.events.Location;
+import java.io.IOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
@@ -58,7 +59,7 @@
* <p>This avoids having to rely on reflection, or on checking whether {@link #getLValue} is
* null.
*/
- public abstract Kind getKind();
+ public Kind getKind();
/**
* The evaluation of the comprehension is based on recursion. Each clause may
@@ -72,23 +73,26 @@
* @param collector the aggregated results of the comprehension.
* @param step the index of the next clause to evaluate.
*/
- abstract void eval(Environment env, OutputCollector collector, int step)
+ void eval(Environment env, OutputCollector collector, int step)
throws EvalException, InterruptedException;
- abstract void validate(ValidationEnvironment env, Location loc) throws EvalException;
+ void validate(ValidationEnvironment env, Location loc) throws EvalException;
/**
* The LValue defined in Clause, i.e. the loop variables for ForClause and null for
* IfClause. This is needed for SyntaxTreeVisitor.
*/
@Nullable // for the IfClause
- public abstract LValue getLValue();
+ public LValue getLValue();
/**
* The Expression defined in Clause, i.e. the collection for ForClause and the
* condition for IfClause. This is needed for SyntaxTreeVisitor.
*/
- public abstract Expression getExpression();
+ public Expression getExpression();
+
+ /** Pretty print to a buffer. */
+ public void prettyPrint(Appendable buffer) throws IOException;
}
/**
@@ -142,8 +146,23 @@
}
@Override
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append("for ");
+ variables.prettyPrint(buffer);
+ buffer.append(" in ");
+ list.prettyPrint(buffer);
+ }
+
+ @Override
public String toString() {
- return Printer.format("for %s in %r", variables.toString(), list);
+ StringBuilder builder = new StringBuilder();
+ try {
+ prettyPrint(builder);
+ } catch (IOException e) {
+ // Not possible for StringBuilder.
+ throw new AssertionError(e);
+ }
+ return builder.toString();
}
}
@@ -186,8 +205,21 @@
}
@Override
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append("if ");
+ condition.prettyPrint(buffer);
+ }
+
+ @Override
public String toString() {
- return String.format("if %s", condition);
+ StringBuilder builder = new StringBuilder();
+ try {
+ prettyPrint(builder);
+ } catch (IOException e) {
+ // Not possible for StringBuilder.
+ throw new AssertionError(e);
+ }
+ return builder.toString();
}
}
@@ -213,14 +245,14 @@
}
@Override
- public String toString() {
- StringBuilder sb = new StringBuilder();
- sb.append(openingBracket()).append(printExpressions());
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append(openingBracket());
+ printExpressions(buffer);
for (Clause clause : clauses) {
- sb.append(' ').append(clause);
+ buffer.append(' ');
+ clause.prettyPrint(buffer);
}
- sb.append(closingBracket());
- return sb.toString();
+ buffer.append(closingBracket());
}
/** Base class for comprehension builders. */
@@ -312,10 +344,8 @@
}
}
- /**
- * Returns a {@link String} representation of the output expression(s).
- */
- abstract String printExpressions();
+ /** Pretty-prints the output expression(s). */
+ protected abstract void printExpressions(Appendable buffer) throws IOException;
abstract OutputCollector createCollector(Environment env);
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Argument.java b/src/main/java/com/google/devtools/build/lib/syntax/Argument.java
index ce1b545..12e8a7b 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Argument.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Argument.java
@@ -14,9 +14,8 @@
package com.google.devtools.build.lib.syntax;
import com.google.devtools.build.lib.util.Preconditions;
-
+import java.io.IOException;
import java.util.List;
-
import javax.annotation.Nullable;
/**
@@ -54,15 +53,20 @@
public boolean isPositional() {
return false;
}
+
public boolean isKeyword() {
return false;
}
- @Nullable public String getName() { // only for keyword arguments
+
+ @Nullable
+ public String getName() { // only for keyword arguments
return null;
}
+
public Expression getValue() {
return value;
}
+
@Override
public void accept(SyntaxTreeVisitor visitor) {
visitor.visit(this);
@@ -76,12 +80,14 @@
super(value);
}
- @Override public boolean isPositional() {
+ @Override
+ public boolean isPositional() {
return true;
}
+
@Override
- public String toString() {
- return String.valueOf(value);
+ public void prettyPrint(Appendable buffer) throws IOException {
+ value.prettyPrint(buffer);
}
}
@@ -95,15 +101,21 @@
this.name = name;
}
- @Override public String getName() {
+ @Override
+ public String getName() {
return name;
}
- @Override public boolean isKeyword() {
+
+ @Override
+ public boolean isKeyword() {
return true;
}
+
@Override
- public String toString() {
- return name + " = " + value;
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append(name);
+ buffer.append(" = ");
+ value.prettyPrint(buffer);
}
}
@@ -114,12 +126,15 @@
super(value);
}
- @Override public boolean isStar() {
+ @Override
+ public boolean isStar() {
return true;
}
+
@Override
- public String toString() {
- return "*" + value;
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append('*');
+ value.prettyPrint(buffer);
}
}
@@ -130,12 +145,15 @@
super(value);
}
- @Override public boolean isStarStar() {
+ @Override
+ public boolean isStarStar() {
return true;
}
+
@Override
- public String toString() {
- return "**" + value;
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append("**");
+ value.prettyPrint(buffer);
}
}
@@ -179,4 +197,12 @@
}
}
}
+
+ @Override
+ public final void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ prettyPrint(buffer);
+ }
+
+ @Override
+ public abstract void prettyPrint(Appendable buffer) throws IOException;
}
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/AssignmentStatement.java b/src/main/java/com/google/devtools/build/lib/syntax/AssignmentStatement.java
index e41e78b..fc2c5fd 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/AssignmentStatement.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/AssignmentStatement.java
@@ -14,6 +14,7 @@
package com.google.devtools.build.lib.syntax;
+import java.io.IOException;
/**
* Syntax node for an assignment statement.
@@ -47,8 +48,12 @@
}
@Override
- public String toString() {
- return lvalue + " = " + expression + '\n';
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ printIndent(buffer, indentLevel);
+ lvalue.prettyPrint(buffer, indentLevel);
+ buffer.append(" = ");
+ expression.prettyPrint(buffer, indentLevel);
+ buffer.append('\n');
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/AugmentedAssignmentStatement.java b/src/main/java/com/google/devtools/build/lib/syntax/AugmentedAssignmentStatement.java
index 5b910ce..cfa2c8f 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/AugmentedAssignmentStatement.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/AugmentedAssignmentStatement.java
@@ -14,6 +14,8 @@
package com.google.devtools.build.lib.syntax;
+import java.io.IOException;
+
/** Syntax node for an augmented assignment statement. */
public final class AugmentedAssignmentStatement extends Statement {
@@ -46,8 +48,14 @@
}
@Override
- public String toString() {
- return String.format("%s %s= %s\n", lvalue, operator, expression);
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ printIndent(buffer, indentLevel);
+ lvalue.prettyPrint(buffer);
+ buffer.append(' ');
+ buffer.append(operator.toString());
+ buffer.append("= ");
+ expression.prettyPrint(buffer);
+ buffer.append('\n');
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/BinaryOperatorExpression.java b/src/main/java/com/google/devtools/build/lib/syntax/BinaryOperatorExpression.java
index de3bf92..ba86818 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/BinaryOperatorExpression.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/BinaryOperatorExpression.java
@@ -19,6 +19,7 @@
import com.google.devtools.build.lib.syntax.Concatable.Concatter;
import com.google.devtools.build.lib.syntax.SkylarkList.MutableList;
import com.google.devtools.build.lib.syntax.SkylarkList.Tuple;
+import java.io.IOException;
import java.util.Collections;
import java.util.IllegalFormatException;
@@ -55,7 +56,22 @@
}
@Override
+ public void prettyPrint(Appendable buffer) throws IOException {
+ // TODO(bazel-team): Possibly omit parentheses when they are not needed according to operator
+ // precedence rules. This requires passing down more contextual information.
+ buffer.append('(');
+ lhs.prettyPrint(buffer);
+ buffer.append(' ');
+ buffer.append(operator.toString());
+ buffer.append(' ');
+ rhs.prettyPrint(buffer);
+ buffer.append(')');
+ }
+
+ @Override
public String toString() {
+ // This omits the parentheses for brevity, but is not correct in general due to operator
+ // precedence rules.
return lhs + " " + operator + " " + rhs;
}
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/BuildFileAST.java b/src/main/java/com/google/devtools/build/lib/syntax/BuildFileAST.java
index d28912f..a0b7464 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/BuildFileAST.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/BuildFileAST.java
@@ -247,8 +247,16 @@
}
@Override
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ // Only statements are printed, not comments and processed import data.
+ for (Statement stmt : stmts) {
+ stmt.prettyPrint(buffer, indentLevel);
+ }
+ }
+
+ @Override
public String toString() {
- return "BuildFileAST" + getStatements();
+ return "<BuildFileAST with " + stmts.size() + " statements>";
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Comment.java b/src/main/java/com/google/devtools/build/lib/syntax/Comment.java
index 27304eb..b0b69c2 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Comment.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Comment.java
@@ -13,6 +13,8 @@
// limitations under the License.
package com.google.devtools.build.lib.syntax;
+import java.io.IOException;
+
/**
* Syntax node for comments.
*/
@@ -34,6 +36,16 @@
}
@Override
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ // We can't really print comments in the right place anyway, due to how their relative order
+ // is lost in the representation of BuildFileAST. So don't bother word-wrapping and just print
+ // it on a single line.
+ printIndent(buffer, indentLevel);
+ buffer.append("# ");
+ buffer.append(value);
+ }
+
+ @Override
public String toString() {
return value;
}
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/ConditionalExpression.java b/src/main/java/com/google/devtools/build/lib/syntax/ConditionalExpression.java
index a891022..4abc12a 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/ConditionalExpression.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/ConditionalExpression.java
@@ -13,6 +13,7 @@
// limitations under the License.
package com.google.devtools.build.lib.syntax;
+import java.io.IOException;
/**
* Syntax node for an if/else expression.
@@ -43,8 +44,12 @@
* Constructs a string representation of the if expression
*/
@Override
- public String toString() {
- return thenCase + " if " + condition + " else " + elseCase;
+ public void prettyPrint(Appendable buffer) throws IOException {
+ thenCase.prettyPrint(buffer);
+ buffer.append(" if ");
+ condition.prettyPrint(buffer);
+ buffer.append(" else ");
+ elseCase.prettyPrint(buffer);
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/DictComprehension.java b/src/main/java/com/google/devtools/build/lib/syntax/DictComprehension.java
index be9191a..fca62c3 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/DictComprehension.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/DictComprehension.java
@@ -13,9 +13,9 @@
// limitations under the License.
package com.google.devtools.build.lib.syntax;
-
import com.google.common.base.Preconditions;
import com.google.devtools.build.lib.events.Location;
+import java.io.IOException;
import java.util.List;
import java.util.Map;
@@ -52,8 +52,10 @@
}
@Override
- String printExpressions() {
- return String.format("%s: %s", keyExpression, valueExpression);
+ protected void printExpressions(Appendable buffer) throws IOException {
+ keyExpression.prettyPrint(buffer);
+ buffer.append(": ");
+ valueExpression.prettyPrint(buffer);
}
/** Builder for {@link DictComprehension}. */
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/DictionaryLiteral.java b/src/main/java/com/google/devtools/build/lib/syntax/DictionaryLiteral.java
index c2328b1..56a62ac 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/DictionaryLiteral.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/DictionaryLiteral.java
@@ -15,6 +15,7 @@
import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.events.Location;
+import java.io.IOException;
import java.util.List;
/**
@@ -42,12 +43,10 @@
}
@Override
- public String toString() {
- StringBuilder sb = new StringBuilder();
- sb.append(key);
- sb.append(": ");
- sb.append(value);
- return sb.toString();
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ key.prettyPrint(buffer);
+ buffer.append(": ");
+ value.prettyPrint(buffer);
}
@Override
@@ -84,17 +83,15 @@
}
@Override
- public String toString() {
- StringBuilder sb = new StringBuilder();
- sb.append("{");
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append("{");
String sep = "";
for (DictionaryEntryLiteral e : entries) {
- sb.append(sep);
- sb.append(e);
+ buffer.append(sep);
+ e.prettyPrint(buffer);
sep = ", ";
}
- sb.append("}");
- return sb.toString();
+ buffer.append("}");
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/DotExpression.java b/src/main/java/com/google/devtools/build/lib/syntax/DotExpression.java
index 97588c0..4672af1 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/DotExpression.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/DotExpression.java
@@ -18,6 +18,7 @@
import com.google.devtools.build.lib.events.Location;
import com.google.devtools.build.lib.syntax.FuncallExpression.MethodDescriptor;
import com.google.devtools.build.lib.util.SpellChecker;
+import java.io.IOException;
/** Syntax node for a dot expression. e.g. obj.field, but not obj.method() */
public final class DotExpression extends Expression {
@@ -40,8 +41,10 @@
}
@Override
- public String toString() {
- return obj + "." + field;
+ public void prettyPrint(Appendable buffer) throws IOException {
+ obj.prettyPrint(buffer);
+ buffer.append('.');
+ field.prettyPrint(buffer);
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Environment.java b/src/main/java/com/google/devtools/build/lib/syntax/Environment.java
index dcfefbd..45abea5 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Environment.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Environment.java
@@ -942,7 +942,8 @@
/**
- * The fail fast handler, which throws a AssertionError whenever an error or warning occurs.
+ * The fail fast handler, which throws an {@link IllegalArgumentException} whenever an error or
+ * warning occurs.
*/
public static final EventHandler FAIL_FAST_HANDLER = new EventHandler() {
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Expression.java b/src/main/java/com/google/devtools/build/lib/syntax/Expression.java
index d5e8e8d..c92eebb 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Expression.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Expression.java
@@ -13,6 +13,8 @@
// limitations under the License.
package com.google.devtools.build.lib.syntax;
+import java.io.IOException;
+
/**
* Base class for all expression nodes in the AST.
*/
@@ -66,4 +68,16 @@
* @see Statement
*/
abstract void validate(ValidationEnvironment env) throws EvalException;
+
+ @Override
+ public final void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ prettyPrint(buffer);
+ }
+
+ /**
+ * Expressions should implement this method instead of {@link #prettyPrint(Appendable, int)},
+ * since the {@code indentLevel} argument is not needed.
+ */
+ @Override
+ public abstract void prettyPrint(Appendable buffer) throws IOException;
}
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/ExpressionStatement.java b/src/main/java/com/google/devtools/build/lib/syntax/ExpressionStatement.java
index 34df3fc..b6fc4c8 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/ExpressionStatement.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/ExpressionStatement.java
@@ -14,6 +14,7 @@
package com.google.devtools.build.lib.syntax;
+import java.io.IOException;
/**
* Syntax node for a function call statement. Used for build rules.
@@ -31,8 +32,10 @@
}
@Override
- public String toString() {
- return expr.toString() + '\n';
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ printIndent(buffer, indentLevel);
+ expr.prettyPrint(buffer);
+ buffer.append('\n');
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/FlowStatement.java b/src/main/java/com/google/devtools/build/lib/syntax/FlowStatement.java
index 63ce6cb..a1639c9 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/FlowStatement.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/FlowStatement.java
@@ -13,6 +13,7 @@
// limitations under the License.
package com.google.devtools.build.lib.syntax;
+import java.io.IOException;
/**
* A class for flow statements (e.g. break and continue)
@@ -54,8 +55,15 @@
void validate(ValidationEnvironment env) throws EvalException {}
@Override
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ printIndent(buffer, indentLevel);
+ buffer.append(kind.name);
+ buffer.append('\n');
+ }
+
+ @Override
public String toString() {
- return kind.name;
+ return kind.name + "\n";
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/ForStatement.java b/src/main/java/com/google/devtools/build/lib/syntax/ForStatement.java
index a43d289..8ac89bd 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/ForStatement.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/ForStatement.java
@@ -16,6 +16,7 @@
import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.syntax.FlowStatement.FlowException;
import com.google.devtools.build.lib.util.Preconditions;
+import java.io.IOException;
import java.util.List;
/**
@@ -52,9 +53,18 @@
}
@Override
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ printIndent(buffer, indentLevel);
+ buffer.append("for ");
+ variable.prettyPrint(buffer);
+ buffer.append(" in ");
+ collection.prettyPrint(buffer);
+ buffer.append(":\n");
+ printSuite(buffer, block, indentLevel);
+ }
+
+ @Override
public String toString() {
- // TODO(bazel-team): if we want to print the complete statement, the function
- // needs an extra argument to specify indentation level.
return "for " + variable + " in " + collection + ": ...\n";
}
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java b/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java
index 2c7a2c8..6312093 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java
@@ -32,6 +32,7 @@
import com.google.devtools.build.lib.util.Pair;
import com.google.devtools.build.lib.util.Preconditions;
import com.google.devtools.build.lib.util.StringUtilities;
+import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
@@ -249,6 +250,23 @@
return numPositionalArgs;
}
+ @Override
+ public void prettyPrint(Appendable buffer) throws IOException {
+ if (obj != null) {
+ obj.prettyPrint(buffer);
+ buffer.append('.');
+ }
+ func.prettyPrint(buffer);
+ buffer.append('(');
+ String sep = "";
+ for (Argument.Passed arg : args) {
+ buffer.append(sep);
+ arg.prettyPrint(buffer);
+ sep = ", ";
+ }
+ buffer.append(')');
+ }
+
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/FunctionDefStatement.java b/src/main/java/com/google/devtools/build/lib/syntax/FunctionDefStatement.java
index e6ef1ba..881368b 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/FunctionDefStatement.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/FunctionDefStatement.java
@@ -14,6 +14,7 @@
package com.google.devtools.build.lib.syntax;
import com.google.common.collect.ImmutableList;
+import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
@@ -69,8 +70,24 @@
}
@Override
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ printIndent(buffer, indentLevel);
+ buffer.append("def ");
+ ident.prettyPrint(buffer);
+ buffer.append('(');
+ String sep = "";
+ for (Parameter<?, ?> param : parameters) {
+ buffer.append(sep);
+ param.prettyPrint(buffer);
+ sep = ", ";
+ }
+ buffer.append("):\n");
+ printSuite(buffer, statements, indentLevel);
+ }
+
+ @Override
public String toString() {
- return "def " + ident + "(" + signature + "):\n";
+ return "def " + ident + "(" + signature + "): ...\n";
}
public Identifier getIdent() {
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Identifier.java b/src/main/java/com/google/devtools/build/lib/syntax/Identifier.java
index ada928b..a404bfa 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Identifier.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Identifier.java
@@ -15,6 +15,7 @@
package com.google.devtools.build.lib.syntax;
import com.google.devtools.build.lib.util.SpellChecker;
+import java.io.IOException;
import java.util.Set;
import javax.annotation.Nullable;
@@ -52,8 +53,8 @@
}
@Override
- public String toString() {
- return name;
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append(name);
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/IfStatement.java b/src/main/java/com/google/devtools/build/lib/syntax/IfStatement.java
index b6adc60..2c0915b 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/IfStatement.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/IfStatement.java
@@ -15,6 +15,7 @@
import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.util.Preconditions;
+import java.io.IOException;
import java.util.List;
/**
@@ -42,6 +43,12 @@
}
}
+ // No prettyPrint function; handled directly by IfStatement#prettyPrint.
+ @Override
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ throw new UnsupportedOperationException("Cannot pretty print ConditionalStatements node");
+ }
+
@Override
public String toString() {
return "[el]if " + condition + ": " + stmts + "\n";
@@ -67,6 +74,7 @@
}
}
+ /** "if" or "elif" clauses. Must be non-empty. */
private final ImmutableList<ConditionalStatements> thenBlocks;
private final ImmutableList<Statement> elseBlock;
@@ -89,11 +97,26 @@
}
@Override
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ String clauseWord = "if ";
+ for (ConditionalStatements condStmt : thenBlocks) {
+ printIndent(buffer, indentLevel);
+ buffer.append(clauseWord);
+ condStmt.getCondition().prettyPrint(buffer);
+ buffer.append(":\n");
+ printSuite(buffer, condStmt.getStmts(), indentLevel);
+ clauseWord = "elif ";
+ }
+ if (!elseBlock.isEmpty()) {
+ printIndent(buffer, indentLevel);
+ buffer.append("else:\n");
+ printSuite(buffer, elseBlock, indentLevel);
+ }
+ }
+
+ @Override
public String toString() {
- // TODO(bazel-team): if we want to print the complete statement, the function
- // needs an extra argument to specify indentation level.
- // As guaranteed by the constructor, there must be at least one element in thenBlocks.
- return String.format("if %s:\n", thenBlocks.get(0).getCondition());
+ return String.format("if %s: ...\n", thenBlocks.get(0).getCondition());
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/IndexExpression.java b/src/main/java/com/google/devtools/build/lib/syntax/IndexExpression.java
index 5a3b813..6d46e71 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/IndexExpression.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/IndexExpression.java
@@ -14,6 +14,7 @@
package com.google.devtools.build.lib.syntax;
import com.google.devtools.build.lib.events.Location;
+import java.io.IOException;
/** Syntax node for an index expression. e.g. obj[field], but not obj[from:to] */
public final class IndexExpression extends Expression {
@@ -36,8 +37,11 @@
}
@Override
- public String toString() {
- return String.format("%s[%s]", obj, key);
+ public void prettyPrint(Appendable buffer) throws IOException {
+ obj.prettyPrint(buffer);
+ buffer.append('[');
+ key.prettyPrint(buffer);
+ buffer.append(']');
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/IntegerLiteral.java b/src/main/java/com/google/devtools/build/lib/syntax/IntegerLiteral.java
index be9ce53..14827fe 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/IntegerLiteral.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/IntegerLiteral.java
@@ -13,6 +13,8 @@
// limitations under the License.
package com.google.devtools.build.lib.syntax;
+import java.io.IOException;
+
/**
* Syntax node for an integer literal.
*/
@@ -23,6 +25,11 @@
}
@Override
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append(value.toString());
+ }
+
+ @Override
public void accept(SyntaxTreeVisitor visitor) {
visitor.visit(this);
}
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/LValue.java b/src/main/java/com/google/devtools/build/lib/syntax/LValue.java
index 72c9ac2..31918ce 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/LValue.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/LValue.java
@@ -17,17 +17,30 @@
import com.google.common.collect.ImmutableSet;
import com.google.devtools.build.lib.events.Location;
import com.google.devtools.build.lib.util.Preconditions;
+import java.io.IOException;
import java.util.Collection;
/**
- * Class representing an LValue.
- * It appears in assignment, for loop and comprehensions, e.g.
- * lvalue = 2
- * [for lvalue in exp]
- * for lvalue in exp: pass
- * An LValue can be a simple variable or something more complex like a tuple.
+ * A term that can appear on the left-hand side of an assignment statement, for loop, comprehension
+ * clause, etc. E.g.,
+ * <ul>
+ * <li>{@code lvalue = 2}
+ * <li>{@code [for lvalue in exp]}
+ * <li>{@code for lvalue in exp: pass}
+ * </ul>
+ *
+ * <p>An {@code LValue}'s expression must have one of the following forms:
+ * <ul>
+ * <li>(Variable assignment) an {@link Identifier};
+ * <li>(Sequence assignment) a {@link ListLiteral} (either list or tuple) of expressions that can
+ * themselves appear in an {@code LValue}; or
+ * <li>(List or dictionary item assignment) an {@link IndexExpression}.
+ * </ul>
+ * In particular and unlike Python, slice expressions, dot expressions, and starred expressions
+ * cannot appear in LValues.
*/
-public class LValue extends ASTNode {
+public final class LValue extends ASTNode {
+
private final Expression expr;
public LValue(Expression expr) {
@@ -211,7 +224,7 @@
}
@Override
- public String toString() {
- return expr.toString();
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ expr.prettyPrint(buffer);
}
}
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/ListComprehension.java b/src/main/java/com/google/devtools/build/lib/syntax/ListComprehension.java
index f5cef33..3a457fb 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/ListComprehension.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/ListComprehension.java
@@ -16,6 +16,7 @@
import com.google.common.base.Preconditions;
import com.google.devtools.build.lib.events.Location;
import com.google.devtools.build.lib.syntax.SkylarkList.MutableList;
+import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
@@ -45,8 +46,8 @@
}
@Override
- String printExpressions() {
- return outputExpression.toString();
+ protected void printExpressions(Appendable buffer) throws IOException {
+ outputExpression.prettyPrint(buffer);
}
/** Builder for {@link ListComprehension}. */
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/ListLiteral.java b/src/main/java/com/google/devtools/build/lib/syntax/ListLiteral.java
index 6f5ece7..fbf145b 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/ListLiteral.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/ListLiteral.java
@@ -15,6 +15,7 @@
import com.google.devtools.build.lib.syntax.SkylarkList.MutableList;
import com.google.devtools.build.lib.syntax.SkylarkList.Tuple;
+import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
@@ -71,6 +72,21 @@
}
@Override
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append(isTuple() ? '(' : '[');
+ String sep = "";
+ for (Expression e : exprs) {
+ buffer.append(sep);
+ e.prettyPrint(buffer);
+ sep = ", ";
+ }
+ if (isTuple() && exprs.size() == 1) {
+ buffer.append(',');
+ }
+ buffer.append(isTuple() ? ')' : ']');
+ }
+
+ @Override
public String toString() {
StringBuilder sb = new StringBuilder();
Printer.printList(sb, exprs, isTuple(), '"', Printer.SUGGESTED_CRITICAL_LIST_ELEMENTS_COUNT,
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Literal.java b/src/main/java/com/google/devtools/build/lib/syntax/Literal.java
index d6842cb..12eec77 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Literal.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Literal.java
@@ -33,11 +33,6 @@
}
@Override
- public String toString() {
- return value.toString();
- }
-
- @Override
Object doEval(Environment env) {
return value;
}
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java b/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java
index a7fc147..d75f21e 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java
@@ -13,9 +13,9 @@
// limitations under the License.
package com.google.devtools.build.lib.syntax;
-import com.google.common.base.Joiner;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
+import java.io.IOException;
import java.util.Map;
/**
@@ -53,9 +53,25 @@
}
@Override
- public String toString() {
- return String.format(
- "load(\"%s\", %s)", imp.getValue(), Joiner.on(", ").join(cachedSymbols));
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ printIndent(buffer, indentLevel);
+ buffer.append("load(");
+ imp.prettyPrint(buffer);
+ for (Identifier symbol : cachedSymbols) {
+ buffer.append(", ");
+ String origName = symbolMap.get(symbol);
+ if (origName.equals(symbol.getName())) {
+ buffer.append('"');
+ symbol.prettyPrint(buffer);
+ buffer.append('"');
+ } else {
+ symbol.prettyPrint(buffer);
+ buffer.append("=\"");
+ buffer.append(origName);
+ buffer.append('"');
+ }
+ }
+ buffer.append(")\n");
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Parameter.java b/src/main/java/com/google/devtools/build/lib/syntax/Parameter.java
index 1b74dcd..5e16ea3 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Parameter.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Parameter.java
@@ -13,6 +13,7 @@
// limitations under the License.
package com.google.devtools.build.lib.syntax;
+import java.io.IOException;
import javax.annotation.Nullable;
/**
@@ -44,27 +45,37 @@
public boolean isMandatory() {
return false;
}
+
public boolean isOptional() {
return false;
}
+
@Override
public boolean isStar() {
return false;
}
+
@Override
public boolean isStarStar() {
return false;
}
- @Nullable public String getName() {
+
+ @Nullable
+ public String getName() {
return name;
}
+
public boolean hasName() {
return true;
}
- @Nullable public T getType() {
+
+ @Nullable
+ public T getType() {
return type;
}
- @Nullable public V getDefaultValue() {
+
+ @Nullable
+ public V getDefaultValue() {
return null;
}
@@ -79,18 +90,20 @@
super(name, type);
}
- @Override public boolean isMandatory() {
+ @Override
+ public boolean isMandatory() {
return true;
}
@Override
- public String toString() {
- return name;
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append(name);
}
}
/** optional parameter (positional or key-only depending on position): Ident = Value */
public static final class Optional<V, T> extends Parameter<V, T> {
+
public final V defaultValue;
public Optional(String name, @Nullable V defaultValue) {
@@ -103,15 +116,29 @@
this.defaultValue = defaultValue;
}
- @Override @Nullable public V getDefaultValue() {
+ @Override
+ @Nullable
+ public V getDefaultValue() {
return defaultValue;
}
- @Override public boolean isOptional() {
+ @Override
+ public boolean isOptional() {
return true;
}
@Override
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append(name);
+ buffer.append('=');
+ // This should only ever be used on a parameter representing static information, i.e. with V
+ // and T instantiated as Expression.
+ ((Expression) defaultValue).prettyPrint(buffer);
+ }
+
+ // Keep this as a separate method so that it can be used regardless of what V and T are
+ // parameterized with.
+ @Override
public String toString() {
return name + "=" + defaultValue;
}
@@ -119,6 +146,7 @@
/** extra positionals parameter (star): *identifier */
public static final class Star<V, T> extends Parameter<V, T> {
+
public Star(@Nullable String name, @Nullable T type) {
super(name, type);
}
@@ -132,21 +160,23 @@
return name != null;
}
- @Override public boolean isStar() {
+ @Override
+ public boolean isStar() {
return true;
}
- @Override public String toString() {
- if (name == null) {
- return "*";
- } else {
- return "*" + name;
+ @Override
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append('*');
+ if (name != null) {
+ buffer.append(name);
}
}
}
/** extra keywords parameter (star_star): **identifier */
public static final class StarStar<V, T> extends Parameter<V, T> {
+
public StarStar(String name, @Nullable T type) {
super(name, type);
}
@@ -155,13 +185,15 @@
super(name);
}
- @Override public boolean isStarStar() {
+ @Override
+ public boolean isStarStar() {
return true;
}
@Override
- public String toString() {
- return "**" + name;
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append("**");
+ buffer.append(name);
}
}
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Printer.java b/src/main/java/com/google/devtools/build/lib/syntax/Printer.java
index 8e04d43..fde22dc 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Printer.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Printer.java
@@ -604,6 +604,13 @@
* <p>If the input string was already shortened and contains "<x more arguments>", this part
* will also be appended.
*/
+ // TODO(bazel-team): Given an input list
+ //
+ // [1, 2, 3, [10, 20, 30, 40, 50, 60], 4, 5, 6]
+ //
+ // the inner list gets doubly mangled as
+ //
+ // [1, 2, 3, [10, 20, 30, 40, <2 more argu...<2 more arguments>], <3 more arguments>]
private void appendTrailingSpecialChars(CharSequence csq, int limit) throws IOException {
int length = csq.length();
Matcher matcher = ARGS_PATTERN.matcher(csq);
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/ReturnStatement.java b/src/main/java/com/google/devtools/build/lib/syntax/ReturnStatement.java
index 45889a4..3c8ac34 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/ReturnStatement.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/ReturnStatement.java
@@ -14,6 +14,7 @@
package com.google.devtools.build.lib.syntax;
import com.google.devtools.build.lib.events.Location;
+import java.io.IOException;
/**
* A wrapper Statement class for return expressions.
@@ -61,8 +62,16 @@
}
@Override
- public String toString() {
- return "return " + returnExpression;
+ public void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
+ printIndent(buffer, indentLevel);
+ buffer.append("return");
+ // "return" with no arg is represented internally as returning the None identifier.
+ if (!(returnExpression instanceof Identifier
+ && ((Identifier) returnExpression).getName().equals("None"))) {
+ buffer.append(' ');
+ returnExpression.prettyPrint(buffer, indentLevel);
+ }
+ buffer.append('\n');
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkImports.java b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkImports.java
index b2ddcc0..9d28ee8 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkImports.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkImports.java
@@ -24,7 +24,11 @@
/**
* Factory class for creating appropriate instances of {@link SkylarkImports}.
*/
-public abstract class SkylarkImports {
+public class SkylarkImports {
+
+ private SkylarkImports() {
+ throw new IllegalStateException("This class should not be instantiated");
+ }
// Default implementation class for SkylarkImport.
private abstract static class SkylarkImportImpl implements SkylarkImport {
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SliceExpression.java b/src/main/java/com/google/devtools/build/lib/syntax/SliceExpression.java
index 14988f0..f3ef277 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SliceExpression.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SliceExpression.java
@@ -14,6 +14,7 @@
package com.google.devtools.build.lib.syntax;
import com.google.devtools.build.lib.events.Location;
+import java.io.IOException;
import java.util.List;
/** Syntax node for an index expression. e.g. obj[field], but not obj[from:to] */
@@ -48,16 +49,34 @@
}
@Override
- public String toString() {
- return String.format("%s[%s:%s%s]",
- obj,
- start,
- // Omit `end` if it's a literal `None` (default value)
- ((end instanceof Identifier) && (((Identifier) end).getName().equals("None"))) ? "" : end,
- // Omit `step` if it's an integer literal `1` (default value)
- ((step instanceof IntegerLiteral) && (((IntegerLiteral) step).value.equals(1)))
- ? "" : ":" + step
- );
+ public void prettyPrint(Appendable buffer) throws IOException {
+ boolean startIsDefault =
+ (start instanceof Identifier) && ((Identifier) start).getName().equals("None");
+ boolean endIsDefault =
+ (end instanceof Identifier) && ((Identifier) end).getName().equals("None");
+ boolean stepIsDefault =
+ (step instanceof IntegerLiteral) && ((IntegerLiteral) step).getValue().equals(1);
+
+ obj.prettyPrint(buffer);
+ buffer.append('[');
+ // Start and end are omitted if they are the literal identifier None, which is the default value
+ // inserted by the parser if no bound is given. Likewise, step is omitted if it is the literal
+ // integer 1.
+ //
+ // The first separator colon is unconditional. The second separator appears only if step is
+ // printed.
+ if (!startIsDefault) {
+ start.prettyPrint(buffer);
+ }
+ buffer.append(':');
+ if (!endIsDefault) {
+ end.prettyPrint(buffer);
+ }
+ if (!stepIsDefault) {
+ buffer.append(':');
+ step.prettyPrint(buffer);
+ }
+ buffer.append(']');
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/StringLiteral.java b/src/main/java/com/google/devtools/build/lib/syntax/StringLiteral.java
index 640d007..df559fe 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/StringLiteral.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/StringLiteral.java
@@ -13,6 +13,8 @@
// limitations under the License.
package com.google.devtools.build.lib.syntax;
+import java.io.IOException;
+
/**
* Syntax node for a string literal.
*/
@@ -23,8 +25,8 @@
}
@Override
- public String toString() {
- return Printer.repr(value);
+ public void prettyPrint(Appendable buffer) throws IOException {
+ buffer.append(Printer.repr(value));
}
@Override
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/UnaryOperatorExpression.java b/src/main/java/com/google/devtools/build/lib/syntax/UnaryOperatorExpression.java
index 5c36be4..b808182 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/UnaryOperatorExpression.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/UnaryOperatorExpression.java
@@ -15,6 +15,8 @@
import com.google.devtools.build.lib.events.Location;
+import java.io.IOException;
+
/** Syntax node for a unary operator expression. */
public final class UnaryOperatorExpression extends Expression {
@@ -36,9 +38,23 @@
}
@Override
+ public void prettyPrint(Appendable buffer) throws IOException {
+ // TODO(bazel-team): Possibly omit parentheses when they are not needed according to operator
+ // precedence rules. This requires passing down more contextual information.
+ buffer.append(operator.toString());
+ buffer.append('(');
+ operand.prettyPrint(buffer);
+ buffer.append(')');
+ }
+
+ @Override
public String toString() {
// All current and planned unary operators happen to be prefix operators.
// Non-symbolic operators have trailing whitespace built into their name.
+ //
+ // Note that this omits the parentheses for brevity, but is not correct in general due to
+ // operator precedence rules. For example, "(not False) in mylist" prints as
+ // "not False in mylist", which evaluates to opposite results in the case that mylist is empty.
return operator.toString() + operand;
}
