大戏法:帮忙翻译Syntax rules

Syntax rules
1. Logical expression can be simple logical variables or complex logical tests involving variables, constants, functional operators, and logical operators. Both the logical expression and the assignment expression can use any of the numeric or string functions allowed in COMPUTE transformations (see COMPUE and transformation expression) on p.51
2. Parentheses can be used to enclose the logical expression. Parentheses can also be used within the logical expression to specify the order of operations. Extra blanks or parentheses can be used to make the expression easier to read.
3. A relation can compare variables, constants, or more complicated arithmetic expressions. Relations cannot be abbreviated. For example, (A EQ 2 OR A EQ 5) is valid, while (A EQ 2 OR 5) is not. Blanks (not commas) must be used to separate relational operators from the expressions being compared.
4. A relation cannot compare a string variable to a numeric variable, or vice versa. A relation cannot compare the result of the logical functions SYSMIS, MISSING, ANY, or RANGE to a number.
5. String values used in expression must be specified in quotes and must include any leading or trailing blanks. Lowercase letters are considered distinct from uppercase letters.
6. String variables that are used as target variables must already exit. To declare a new string variables, first create the variable with the STRING command and then specify the new variable as the target variable on IF.