Put statement in data step can not put a date constant properly?

[Steve1964]

when I run the following code,I get an error message

data test;

put '01JAN2019'd ;

run;

The data step codes in the following run smoothly without error.

data test ;

x= '01JAN2019'd ;

put x;

run;

Why put statement can not work properly in the first data step? since the data constant '01JAN2019'd is  valid.  

[heffo]

It seems like it is because SAS don't want to be confused or that it actually get confused. 

Avoiding a Common Error When Writing Both a Character Constant and a Variable

When using a PUT statement to write a character constant that is followed by a variable name, always put a blank space between the closing quotation mark and the variable name:

put 'Player:' name1 'Player:' name2 'Player:' name3;

Otherwise, SAS might interpret a character constant that is followed by a variable name as a special SAS constant as illustrated in this table.

Characters That Cause Misinterpretation When They Follow a Character Constant

Starting Letter of Variable Represents Examples

b	bit testing constant	'00100000'b
d	date constant	'01jan04'd
dt	datetime constant	'18jan2003:9:27:05am'dt
n	name literal	'My Table'n
t	time constant	'9:25:19pm't
x	hexadecimal notation	'534153'x

http://support.sas.com/documentation/cdl/en/lestmtsref/63323/HTML/default/viewer.htm#n1spe7nmkmi7ywn...

[ChrisNZ]

> Why put statement can not work properly in the first data step? 

For the same reason that 

data test;
  put 1 ;
run;

does not work.

The PUT statement accepts a long list of arguments, but not a number.

See the documentation linked to in the previous reply.

[Kurt_Bremser · Accepted solution]

When encountered in the code during compilation, the date constant is imnediately converted to its real value (a number). Since numbers in put statements have special meaning with regards to positions, this then causes your ERROR.