I think the legend goes Wirth created the Pascal language to be the most easily compilable. To show my age, I recall a class used Modula-2 when I was in college, also from Wirth, very Pascal-like.
https://gcc.gnu.org/onlinedocs/gcc-15.2.0/gm2
Even available on compiler explorer to play with, https://godbolt.org/z/ev9Pbxn9K
Yes, that was a common trend across all programming languages designed by him.
That is also how P-Code came to be, he didn't want to create a VM for Pascal, rather the goal was to make porting easier, by requiring only a basic P-Code interpreter, it was very easy to port Pascal, a design approach he kept for Modula-2 (M-Code) and Oberon (Slim binaries).
I have never been able to determine whether Wirth knew of this work, but, given that Richards's 1969 BCPL paper described OCode, I suspect he was aware of it, and that it influenced his design of the Pascal-P compiler. (I am not sure when Intcode appeared, but it was present when I obtained the BCPL compiler in 1972, a year before the Pascal-P release.)
Would you mind posting links to the relevant papers?
https://beckassets.blob.core.windows.net/product/readingsamp...
And there's the chapter 7 in the Richard's book (1979): https://archive.org/details/richards1979bcpl/page/n131/mode/...
You will find much more information and references at the software preservation site.
Your last link (BCPL history) contains links to a lot of papers (all?) by Martin Richards one of which is (pdf) INTCODE - An Interpretive Machine Code for BCPL which i presume was what "vincent-manis" was referring to in addition to the other papers on BCPL Language/Compiler/Manuals. Seems quite comprehensive, i must say.
We really need to publicize all of Martin Richards' contributions to computer science. He seems to be one of those unsung heroes mentioned everywhere having contributed to Languages/Compilers/VMs/OSes but not that well-known.
From the site;
BCPL—the language and systems built with it—connects the first few generations of computer scientists and software engineers, spanning mainframes to minis to micros. It was driven from the UK, but with a tributary into the heart of US research institutions, where it begat C, the most popular systems programming language of all time.
If fact there were all operating systems written with such ideas like Burroughs B5000 in 1961, nowadays still sold by Unisys, and thanks to this approach being easily retargeted to modern hardware.
Why this "who did it first thread?" in first place?
Regarding the popular opinion here that Pascal was created for educational purposes (only) - implicitly meaning not for building real, large-scale software - Wirth considered these two characteristics equivalent, and in his view one was a necessary condition for the other.
From the summary/abstract of his original publication about Pascal (The Programming Language Pascal) written in 1970 and published in Acta Informatica in 1971:
In view of its intended usage both as a convenient basis to teach programming and as an efficient tool to write large programs, emphasis was placed on keeping the number of fundamental concepts reasonably small, on a simple and systematic language structure, and on efficient implementability.
1. To use it in teaching a structure programming course to new students. As in the late 60's all student programming was batch mode (submit your program to an operator to run, and pick up the printout the following day), this meant the compiler had to be single-pass and give good error messages.
2. To use it in teaching a data structures course involving new data structures worked out by Wirth and Hoare.
3. To use it in teaching a compilers course. This meant the compiler code had to be clean and understandable. Being single-pass helped in this.
I think it was more that it would be easy to write a compiler for, which meant that CS students could write one. Don't have a source for this that I can remember, though.