com.google.template.soy.pysrc.restricted

Class PyExprUtils

java.lang.Object

com.google.template.soy.pysrc.restricted.PyExprUtils

public final class PyExprUtils
extends Object

Common utilities for dealing with Python expressions.

Important: This class may only be used in implementing plugins (e.g. functions, directives).

Field Summary

Fields

Modifier and Type	Field and Description
static String	TRANSLATOR_NAME The variable name used to reference the current translator instance.

Method Summary

Modifier and Type	Method and Description
static PyExpr	concatPyExprs(List<? extends PyExpr> pyExprs) Builds one Python expression that computes the concatenation of the given Python expressions.
static PyExpr	convertIterableToPyListExpr(Iterable<?> iterable) Convert a java Iterable object to valid PyExpr as array.
static PyExpr	convertIterableToPyTupleExpr(Iterable<?> iterable) Convert a java Iterable object to valid PyExpr as tuple.
static PyExpr	convertMapToOrderedDict(Map<PyExpr,PyExpr> dict) Convert a java Map to valid PyExpr as dict.
static PyExpr	convertMapToPyExpr(Map<PyExpr,PyExpr> dict) Convert a java Map to valid PyExpr as dict.
static String	genExprWithNewToken(Operator op, List<? extends TargetExpr> operandExprs, String newToken) Generates an expression for the given operator and operands assuming that the expression for the operator uses the same syntax format as the Soy operator, with the exception that the of a different token.
static PyExpr	genPyNotNullCheck(PyExpr pyExpr) Generates a Python not null (None) check expression for the given PyExpr.
static PyExpr	genPyNullCheck(PyExpr expr) Generates a Python null (None) check expression for the given PyExpr.
static PyExpr	maybeProtect(PyExpr expr, int minSafePrecedence) Wraps an expression with parenthesis if it's not above the minimum safe precedence.
static int	pyPrecedenceForOperator(Operator op) Provide the Python operator precedence for a given operator.
static PyExpr	wrapAsSanitizedContent(SanitizedContent.ContentKind contentKind, PyExpr pyExpr) Deprecated. this method is not safe to use without a security review. Do not use it.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

TRANSLATOR_NAME

public static final String TRANSLATOR_NAME

The variable name used to reference the current translator instance.

See Also:

Constant Field Values

Method Detail

concatPyExprs

public static PyExpr concatPyExprs(List<? extends PyExpr> pyExprs)

Builds one Python expression that computes the concatenation of the given Python expressions.

Python doesn't allow arbitrary concatentation between types, so to ensure type safety and consistent behavior, coerce all expressions to Strings before joining them. Python's array joining mechanism is used in place of traditional concatenation to improve performance.

Parameters:

pyExprs - The Python expressions to concatenate.

Returns:

One Python expression that computes the concatenation of the given Python expressions.

genPyNotNullCheck

public static PyExpr genPyNotNullCheck(PyExpr pyExpr)

Generates a Python not null (None) check expression for the given PyExpr.

genPyNullCheck

public static PyExpr genPyNullCheck(PyExpr expr)

Generates a Python null (None) check expression for the given PyExpr.

maybeProtect

public static PyExpr maybeProtect(PyExpr expr,
                                  int minSafePrecedence)

Wraps an expression with parenthesis if it's not above the minimum safe precedence.

NOTE: For the sake of brevity, this implementation loses typing information in the expressions.

Parameters:

expr - The expression to wrap.

minSafePrecedence - The minimum safe precedence (not inclusive).

Returns:

The PyExpr potentially wrapped in parenthesis.

wrapAsSanitizedContent

@Deprecated
public static PyExpr wrapAsSanitizedContent(SanitizedContent.ContentKind contentKind,
                                                        PyExpr pyExpr)

Deprecated. this method is not safe to use without a security review. Do not use it.

Wraps an expression with the proper SanitizedContent constructor.

NOTE: The pyExpr provided must be properly escaped for the given ContentKind. Please talk to ISE (ise@) for any questions or concerns.

Parameters:

contentKind - The kind of sanitized content.

pyExpr - The expression to wrap.

pyPrecedenceForOperator

public static int pyPrecedenceForOperator(Operator op)

Provide the Python operator precedence for a given operator.

Parameters:

op - The operator.

Returns:

THe python precedence as an integer.

convertIterableToPyListExpr

public static PyExpr convertIterableToPyListExpr(Iterable<?> iterable)

Convert a java Iterable object to valid PyExpr as array.

Parameters:

iterable - Iterable of Objects to be converted to PyExpr, it must be Number, PyExpr or String.

convertIterableToPyTupleExpr

public static PyExpr convertIterableToPyTupleExpr(Iterable<?> iterable)

Convert a java Iterable object to valid PyExpr as tuple.

Parameters:

iterable - Iterable of Objects to be converted to PyExpr, it must be Number, PyExpr or String.

convertMapToOrderedDict

public static PyExpr convertMapToOrderedDict(Map<PyExpr,PyExpr> dict)

Convert a java Map to valid PyExpr as dict.

Parameters:

dict - A Map to be converted to PyExpr as a dictionary, both key and value should be PyExpr.

convertMapToPyExpr

public static PyExpr convertMapToPyExpr(Map<PyExpr,PyExpr> dict)

Convert a java Map to valid PyExpr as dict.

Parameters:

dict - A Map to be converted to PyExpr as a dictionary, both key and value should be PyExpr.

genExprWithNewToken

public static String genExprWithNewToken(Operator op,
                                         List<? extends TargetExpr> operandExprs,
                                         String newToken)

Generates an expression for the given operator and operands assuming that the expression for the operator uses the same syntax format as the Soy operator, with the exception that the of a different token. Associativity, spacing, and precedence are maintained from the original operator.

Examples:

 NOT, ["$a"], "!" -> "! $a"
 AND, ["$a", "$b"], "&&" -> "$a && $b"
 NOT, ["$a * $b"], "!"; -> "! ($a * $b)"
 

Parameters:

op - The operator.

operandExprs - The operands.

newToken - The language specific token equivalent to the operator's original token.

Returns:

The generated expression with a new token.