Let me take up a few unrelated topics that have been overdue for some discussion in this column.

First, why doesn't The Post print full texts of presidential commentary --speeches, press conferences, State of the Union messages, public exchanges with other heads of government--a question raised by a fair number of readers recently. The bottom line, all editors contend, is the tyranny of space. Competition for the "news hole" each day among national, foreign and metro desks is an exercise in compromise. Consequently, newsworthy presidential texts are published as excerpts or sometimes omitted altogether. The explanation may be understandable, but not satisfactory to certain readers.

When editors left out the first four paragraphs of President Reagan's Christmas speech in which he addressed the situation in Poland, the paper "caught hell" from various quarters. Among the omitted lines the president said: "Some celebrate Christmas as the birthday of a great and good philosopher and teacher. Others of us believe in the divinity of the Child born in Bethlehem . . . He who could perform miracles chose to come among us as a helpless babe . . . His first great lesson that we should learn to care for one another."

Viewing the remarks as a statement of the president's religious conviction, Rev. John E. Boyles of The National Presbyterian Church wrote that the deletion amounted to ". . . a clear case of religious bias . . . particularly anti- Christian bias." Told that that was an unwarranted conclusion and that the true reason was space, Rev. Boyles argued other material might have been cut as easily. He pointed specifically to a four-paragraph item, unrelated to the speech, that ran at the bottom of the same page. I agreed that the space would have been better used to keep the president's speech intact.

Other readers were disappointed that the State of the Union message was not printed in full. The paper carried a full page of excerpts in addition to five news stories and one analysis piece. This did not satisfy those who "wanted to read it for themselves."

A similar view was publicly aired by The Wall Street Journal's senior columnist, Vermont Royster. What he wanted was to read "what the man said" and, among other places, looked for the full text in The Post. About the news stories in different papers, he said, "I found not so much as a single paragraph of connected sentences quoted directly from the president." While he looked for more from The Post, he didn't say whether his own paper should have carried the messsage as did The New York Times. Looking for more from The Post is a form of flattery, perhaps.

Last week, the paper neglected to publish an exchange of letters between President Reagan and Israeli Prime Minister Menachem Begin. The letters capped a two-day story between Jerusalem and Washington that The Post had amply reported. Again, the explanation was prohibitive space, and the stories contained sufficient substance to ensure the readership was informed. I agreed with some others that failing to carry the letters was to leave out an important element from the record of the story.

Recently, the text of a presidential press conference was passed over entirely. The consensus was that the conference was not sufficiently newsworthy, and the three stories that did run were adequate to the event. By contrast, The New York Times carried the full text and five stories.

The Post makes no pretense at being a paper "of record" like The New York Times. Managing Editor Howard Simons argues that The Post compiles its record with reportage. For example, he points to the legislative process. The Post provides continuing coverage of important issues through Congress, "from subcommittee to floor vote to conference." This prochat couless provides a kind of track record to which citizens can refer should they choose to intervene--something akin to knowing at all times where the action is.

Mr. Simons acknowledges the primacy of The New York Times, which carries official documentation, but he maintains this is not the only "record" of value to a readership. Presidential and other official texts will be published when editors agree they have inherent news value, not just because they're there, in his view. Go for more, not less, is this one's view.

A different topic involves The Post and the Middle East plan put forward by Crown Prince Fahd of Saudi Arabia. Some readers took issue with a story from Beirut a while back that, among other things, said the plan "proposes the establishment of a Palestinian state with its capital in Arab East Jerusalem." The critics maintained the plan envisaged the capital to take in all of Jerusalem.

In an initial exchange, I said I didn't believe that to be so, but if the paper was in error it should be corrected. Meanwhile, the Department of State confirmed the paper's understanding. Next, one critic sent an excerpt from a report of a private symposium at Seven Springs Center, N.Y., last summer. The reference on this point, "according to press translation," reads: "an independent Palestinian state should be established with Jerusalem as its capital." With this came a request for a correction.

But a further check with the State Department reconfirmed the newspaper's understanding. Now, an official translation by the Saudi Arabian government, issued by its embassy in Washington, says clearly: "Establishment of the independent State of Palestine with its capital, East Jerusalem." If there was any question, this effectively answers it.

Finally, Post coverage of the Georgetown waterfront and the dispute between those advocating commercial development and those favoring a park has been subject to criticism. Because it has been overlooked in stories to date, I want here only to note that among those wanting "full park use of the waterfront" are a number of citywide and national organizations, not just Georgetown citizens' groups. A list compiled by the Human Environment Center identifies 25 such organizations too numerous to list here; but it includes the National Audubon Society, National Wildlife Federation, National Council of La Raza and National Council of Negro Women.