www.digitalmars.com         C & C++   DMDScript  

digitalmars.D - From where come from the term "lowering"?

reply "Asman01" <jckj33 gmail.com> writes:
I was reading Walter's article where he use this term and explain 
what is it. He did a clear explanation abount what what it does. 
But where come from actually this term? I can't find anything 
related with a lot of keyword combinations on google/bing. And 
isn't only me want to know about origin of this term 
(http://stackoverflow.com/questions/20252876/wanted-good-definition-of-the-term-lowering-in-the-context-of-compilers)
Mar 16 2014
next sibling parent reply "H. S. Teoh" <hsteoh quickfur.ath.cx> writes:
On Mon, Mar 17, 2014 at 12:42:26AM +0000, Asman01 wrote:

 I was reading Walter's article where he use this term and explain
 what is it. He did a clear explanation abount what what it does. But
 where come from actually this term? I can't find anything related
 with a lot of keyword combinations on google/bing. And isn't only me
 want to know about origin of this term
(http://stackoverflow.com/questions/20252876/wanted-good-definition-of-the-term-lowering-in-the-context-of-compilers)


I don't know about the exact etymology of this term, but my
understanding of it is that it's referring to the translation of a
higher-level concept to a lower-level implementation, such as the
translation of a C construct into assembly language, or the translation
of a C++ construct into C (which the first C++ compilers did). In the
context of D, it can also be used to describe a particular syntax that
translates to "simpler" or lower-level primitives, such as:

	foreach (i; 0 .. 10) { ... }

translating into:

	for (i=0; i < 10; i++) { ... }

Hence the term "lowering" (take a high-level abstraction and translate
it into a lower-level implementation).


T

-- 
Only boring people get bored. -- JM
Mar 17 2014
parent "Asman01" <jckj33 gmail.com> writes:
On Monday, 17 March 2014 at 16:49:38 UTC, H. S. Teoh wrote:

 On Mon, Mar 17, 2014 at 12:42:26AM +0000, Asman01 wrote:

 I was reading Walter's article where he use this term and 
 explain
 what is it. He did a clear explanation abount what what it 
 does. But
 where come from actually this term? I can't find anything 
 related
 with a lot of keyword combinations on google/bing. And isn't 
 only me
 want to know about origin of this term 
 (http://stackoverflow.com/questions/20252876/wanted-good-definition-of-the-term-lowering-in-the-context-of-compilers)


 I don't know about the exact etymology of this term, but my
 understanding of it is that it's referring to the translation 
 of a
 higher-level concept to a lower-level implementation, such as 
 the
 translation of a C construct into assembly language, or the 
 translation
 of a C++ construct into C (which the first C++ compilers did). 
 In the
 context of D, it can also be used to describe a particular 
 syntax that
 translates to "simpler" or lower-level primitives, such as:

 	foreach (i; 0 .. 10) { ... }

 translating into:

 	for (i=0; i < 10; i++) { ... }

 Hence the term "lowering" (take a high-level abstraction and 
 translate
 it into a lower-level implementation).


 T


This I have had understood. What I was looking know is where come 
from the term because I hadn't saw nobody also Walter/Andrei 
using this.
Mar 17 2014
prev sibling parent reply Andrei Alexandrescu <SeeWebsiteForEmail erdani.org> writes:
On 3/16/14, 5:42 PM, Asman01 wrote:

 I was reading Walter's article where he use this term and explain what
 is it. He did a clear explanation abount what what it does. But where
 come from actually this term? I can't find anything related with a lot
 of keyword combinations on google/bing. And isn't only me want to know
 about origin of this term
 (http://stackoverflow.com/questions/20252876/wanted-good-definition-of-the-term-lowering-in-the-context-of-compilers)


I introduced the term "lowering" to our community as the word was 
commonly used in the programming languages group at University of 
Washington (led at the time by Craig Chambers and Dan Grossman). It's 
commonly used in compiler backend circles, see e.g. http://goo.gl/FEVypJ.

It generally means the process of translating a higher-level language 
with many capabilities into a simpler, lower-level language. The latter 
could be an intermediate language, machine code, or even a reduced 
dialect of the higher-level language (as is the case for the way it's 
often used in D).


Andrei
Mar 17 2014
parent "Asman01" <jckj33 gmail.com> writes:
On Monday, 17 March 2014 at 16:57:46 UTC, Andrei Alexandrescu 
wrote:

 On 3/16/14, 5:42 PM, Asman01 wrote:

 I was reading Walter's article where he use this term and 
 explain what
 is it. He did a clear explanation abount what what it does. 
 But where
 come from actually this term? I can't find anything related 
 with a lot
 of keyword combinations on google/bing. And isn't only me want 
 to know
 about origin of this term
 (http://stackoverflow.com/questions/20252876/wanted-good-definition-of-the-term-lowering-in-the-context-of-compilers)


 I introduced the term "lowering" to our community as the word 
 was commonly used in the programming languages group at 
 University of Washington (led at the time by Craig Chambers and 
 Dan Grossman). It's commonly used in compiler backend circles, 
 see e.g. http://goo.gl/FEVypJ.

 It generally means the process of translating a higher-level 
 language with many capabilities into a simpler, lower-level 
 language. The latter could be an intermediate language, machine 
 code, or even a reduced dialect of the higher-level language 
 (as is the case for the way it's often used in D).


 Andrei


Thanks very much for the information.
Mar 17 2014