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neauoire committed Aug 2, 2023
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71 changes: 61 additions & 10 deletions site/uxntal_lambdas.html
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<header><a href="home.html"><img alt="XXIIVV" src="../media/icon/logo.svg"></a></header>
<nav><ul><li><a href="uxntal_opcodes.html">uxntal opcodes</a></li><li><a href="uxntal_stacks.html">uxntal stacks</a></li><li><a href="uxntal_modes.html">uxntal modes</a></li><li><a href="uxntal_syntax.html" class="parent">uxntal syntax</a></li><li><a href="uxntal_immediate.html">uxntal immediate</a></li><li><a href="uxntal_memory.html">uxntal memory</a></li><li><a href="uxntal_state.html">uxntal state</a></li><li><a href="uxntal_devices.html">uxntal devices</a></li><li><a href="uxntal_errors.html">uxntal errors</a></li></ul><ul><li><a href="uxntal_types.html">uxntal types</a></li><li><a href="uxntal_struct.html">uxntal struct</a></li><li><a href="uxntal_lambdas.html" class="self">uxntal lambdas</a></li><li><a href="uxntal_cons.html">uxntal cons</a></li><li><a href="uxntal_library.html">uxntal library</a></li></ul><ul></ul></nav><main><h2>Anonymous Functions in Uxntal</h2>

<p>In the context of Uxntal, lambdas are unlabeled inline routines, delimited by
<p>In the context of Uxntal, lambdas are unlabeled inline routines delimited by
curlies. A lambda block is jumped over, and a pointer to the start of the
lambda is pushed to the top of the working stack.</p>

<p>A higher-order function is a function that takes a function as an argument or
returns one as a result. In the following example, the foreach routine is
expecting a pointer to a series of bytes, and a pointer to a function to apply
on each byte-long item in memory.</p>
lambda is pushed to the top of the working stack. The body of the lambda can be
unquoted with the <kbd>JSR2</kbd> opcode.</p>

<pre>
;bytes { DUP ADD JMP2r } foreach
#12 #34 { ADD JMP2r } JSR2
</pre>

<p>A lambda can be used to store data inline, and ensure that the content is not
inadvertenly run.</p>

<pre>
{ "hello $1 } print-lambda
{ "hello } print-lambda
</pre>

<p>Under the hood, the lambda block writes the length to jump by, and that
Expand All @@ -36,7 +32,62 @@
POP2 POP2 JMP2r
</pre>

<p>Only the outermost layer of a nested lambda is evaluated:</p>
<p>A higher-order function is a function that takes a function as an argument or
returns one as a result. In the following example, the foreach routine is
expecting a pointer to a series of bytes, and a pointer to a function to apply
on each byte-long item in memory.</p>

<pre>
{ 01 02 03 04 05 } ;double foreach
</pre>

<p>The body of the <code>double</code> function reads the value of a cell in
memory and writes a result equal to twice its value, and the body of the
<code>foreach</code> function is merely applying a function to each cell in
memory.</p>

<pre>
@double ( addr* -- addr* )
STH2k LDAk
DUP ADD
STH2r STA
JMP2r

@foreach ( bytes* fn* -- bytes* )
,&t STR2
DUP2k #0002 SUB2 LDA2 ADD2 SWP2
&l ( -- )
[ LIT2 &t $2 ] JSR2 INC2 GTH2k ?&l
POP2 POP2 JMP2r
</pre>

<p>Consider that the whole <code>double</code> function can equally be
inlined:</p>

<pre>
{ 01 02 03 04 05 } { STH2k LDAk DUP ADD STH2r STA JMP2r } foreach
</pre>

<p>As another demonstration of the same concept, we can inline a list of items,
here's an implementation of Lisp's member function that returns the member in a
list, or <i>nil</i>.</p>

<pre>
{ =cat =dog =bat } ;rat member
</pre>

<pre>
@member ( {items}* target* -- res/-1* )
,&t STR2
DUP2k #0002 SUB2 LDA2 ADD2 SWP2
&l ( -- )
LDA2k [ LIT2 &t $2 ] EQU2 ?&found
INC2 INC2 GTH2k ?&l
POP2 ;nil &found NIP2 JMP2r
</pre>

<p>Lambdas can also be nested into one another, but remember, only the outermost
layer of a nested lambda is evaluated at a time:</p>

<pre>
#01 { { "foo $1 } !print-lambda } JCN2
Expand Down
71 changes: 61 additions & 10 deletions site/uxntal_syntax.html
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Expand Up @@ -161,24 +161,20 @@ <h3>Example</h3>

<h2>Anonymous Functions in Uxntal</h2>

<p>In the context of Uxntal, lambdas are unlabeled inline routines, delimited by
<p>In the context of Uxntal, lambdas are unlabeled inline routines delimited by
curlies. A lambda block is jumped over, and a pointer to the start of the
lambda is pushed to the top of the working stack.</p>

<p>A higher-order function is a function that takes a function as an argument or
returns one as a result. In the following example, the foreach routine is
expecting a pointer to a series of bytes, and a pointer to a function to apply
on each byte-long item in memory.</p>
lambda is pushed to the top of the working stack. The body of the lambda can be
unquoted with the <kbd>JSR2</kbd> opcode.</p>

<pre>
;bytes { DUP ADD JMP2r } foreach
#12 #34 { ADD JMP2r } JSR2
</pre>

<p>A lambda can be used to store data inline, and ensure that the content is not
inadvertenly run.</p>

<pre>
{ "hello $1 } print-lambda
{ "hello } print-lambda
</pre>

<p>Under the hood, the lambda block writes the length to jump by, and that
Expand All @@ -193,7 +189,62 @@ <h2>Anonymous Functions in Uxntal</h2>
POP2 POP2 JMP2r
</pre>

<p>Only the outermost layer of a nested lambda is evaluated:</p>
<p>A higher-order function is a function that takes a function as an argument or
returns one as a result. In the following example, the foreach routine is
expecting a pointer to a series of bytes, and a pointer to a function to apply
on each byte-long item in memory.</p>

<pre>
{ 01 02 03 04 05 } ;double foreach
</pre>

<p>The body of the <code>double</code> function reads the value of a cell in
memory and writes a result equal to twice its value, and the body of the
<code>foreach</code> function is merely applying a function to each cell in
memory.</p>

<pre>
@double ( addr* -- addr* )
STH2k LDAk
DUP ADD
STH2r STA
JMP2r

@foreach ( bytes* fn* -- bytes* )
,&t STR2
DUP2k #0002 SUB2 LDA2 ADD2 SWP2
&l ( -- )
[ LIT2 &t $2 ] JSR2 INC2 GTH2k ?&l
POP2 POP2 JMP2r
</pre>

<p>Consider that the whole <code>double</code> function can equally be
inlined:</p>

<pre>
{ 01 02 03 04 05 } { STH2k LDAk DUP ADD STH2r STA JMP2r } foreach
</pre>

<p>As another demonstration of the same concept, we can inline a list of items,
here's an implementation of Lisp's member function that returns the member in a
list, or <i>nil</i>.</p>

<pre>
{ =cat =dog =bat } ;rat member
</pre>

<pre>
@member ( {items}* target* -- res/-1* )
,&t STR2
DUP2k #0002 SUB2 LDA2 ADD2 SWP2
&l ( -- )
LDA2k [ LIT2 &t $2 ] EQU2 ?&found
INC2 INC2 GTH2k ?&l
POP2 ;nil &found NIP2 JMP2r
</pre>

<p>Lambdas can also be nested into one another, but remember, only the outermost
layer of a nested lambda is evaluated at a time:</p>

<pre>
#01 { { "foo $1 } !print-lambda } JCN2
Expand Down
71 changes: 61 additions & 10 deletions src/htm/uxntal_lambdas.htm
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Original file line number Diff line number Diff line change
@@ -1,23 +1,19 @@
<h2>Anonymous Functions in Uxntal</h2>

<p>In the context of Uxntal, lambdas are unlabeled inline routines, delimited by
<p>In the context of Uxntal, lambdas are unlabeled inline routines delimited by
curlies. A lambda block is jumped over, and a pointer to the start of the
lambda is pushed to the top of the working stack.</p>

<p>A higher-order function is a function that takes a function as an argument or
returns one as a result. In the following example, the foreach routine is
expecting a pointer to a series of bytes, and a pointer to a function to apply
on each byte-long item in memory.</p>
lambda is pushed to the top of the working stack. The body of the lambda can be
unquoted with the <kbd>JSR2</kbd> opcode.</p>

<pre>
;bytes { DUP ADD JMP2r } foreach
#12 #34 { ADD JMP2r } JSR2
</pre>

<p>A lambda can be used to store data inline, and ensure that the content is not
inadvertenly run.</p>

<pre>
{ "hello $1 } print-lambda
{ "hello } print-lambda
</pre>

<p>Under the hood, the lambda block writes the length to jump by, and that
Expand All @@ -32,7 +28,62 @@ <h2>Anonymous Functions in Uxntal</h2>
POP2 POP2 JMP2r
</pre>

<p>Only the outermost layer of a nested lambda is evaluated:</p>
<p>A higher-order function is a function that takes a function as an argument or
returns one as a result. In the following example, the foreach routine is
expecting a pointer to a series of bytes, and a pointer to a function to apply
on each byte-long item in memory.</p>

<pre>
{ 01 02 03 04 05 } ;double foreach
</pre>

<p>The body of the <code>double</code> function reads the value of a cell in
memory and writes a result equal to twice its value, and the body of the
<code>foreach</code> function is merely applying a function to each cell in
memory.</p>

<pre>
@double ( addr* -- addr* )
STH2k LDAk
DUP ADD
STH2r STA
JMP2r

@foreach ( bytes* fn* -- bytes* )
,&t STR2
DUP2k #0002 SUB2 LDA2 ADD2 SWP2
&l ( -- )
[ LIT2 &t $2 ] JSR2 INC2 GTH2k ?&l
POP2 POP2 JMP2r
</pre>

<p>Consider that the whole <code>double</code> function can equally be
inlined:</p>

<pre>
{ 01 02 03 04 05 } { STH2k LDAk DUP ADD STH2r STA JMP2r } foreach
</pre>

<p>As another demonstration of the same concept, we can inline a list of items,
here's an implementation of Lisp's member function that returns the member in a
list, or <i>nil</i>.</p>

<pre>
{ =cat =dog =bat } ;rat member
</pre>

<pre>
@member ( {items}* target* -- res/-1* )
,&t STR2
DUP2k #0002 SUB2 LDA2 ADD2 SWP2
&l ( -- )
LDA2k [ LIT2 &t $2 ] EQU2 ?&found
INC2 INC2 GTH2k ?&l
POP2 ;nil &found NIP2 JMP2r
</pre>

<p>Lambdas can also be nested into one another, but remember, only the outermost
layer of a nested lambda is evaluated at a time:</p>

<pre>
#01 { { "foo $1 } !print-lambda } JCN2
Expand Down

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