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S-expressions: Difference between revisions

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S-expressions (view source)

Revision as of 15:24, 31 March 2022

15,969 bytes added ,  2 years ago
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→‎{{header|Phix}}: syntax coloured
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that may not be clear on the display: 4e-5 and 4-e5 may appear similar but the latter is probably a parse failure. It may
be more sensible for get_term() to raise an error if the scanf fails, than assume it is a symbol like it does now.
<!--<lang Phix>constant s_expr_str = """(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
((data "quoted data" 123 4.5)
<span style="color: #008080;">constant</span> <span style="color: #000000;">s_expr_str</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">"""
(data (!@# (4.5) "(more" "data)")))"""
((data "quoted data" 123 4.5)
 
(data (!@# (4.5) "(more" "data)")))"""</span>
function skip_spaces(string s, integer sidx)
while sidx<=length(s) and find(s[sidx]," \t\r\n") do sidx += 1 end while
<span style="color: #008080;">function</span> <span style="color: #000000;">skip_spaces</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">sidx</span><span style="color: #0000FF;">)</span>
return sidx
<span style="color: #008080;">while</span> <span style="color: #000000;">sidx</span><span style="color: #0000FF;"><=</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">and</span> <span style="color: #7060A8;">find</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">],{</span><span style="color: #008000;">' '</span><span style="color: #0000FF;">,</span><span style="color: #008000;">'\t'</span><span style="color: #0000FF;">,</span><span style="color: #008000;">'\r'</span><span style="color: #0000FF;">,</span><span style="color: #008000;">'\n'</span><span style="color: #0000FF;">})</span> <span style="color: #008080;">do</span> <span style="color: #000000;">sidx</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span> <span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
end function
<span style="color: #008080;">return</span> <span style="color: #000000;">sidx</span>
 
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
function get_term(string s, integer sidx)
-- get a single quoted string, symbol, or number.
<span style="color: #008080;">function</span> <span style="color: #000000;">get_term</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">sidx</span><span style="color: #0000FF;">)</span>
integer ch = s[sidx]
<span style="color: #000080;font-style:italic;">-- get a single quoted string, symbol, or number.</span>
string res = ""
<span style="color: #004080;">integer</span> <span style="color: #000000;">ch</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">]</span>
if ch='\"' then
<span style="color: #004080;">string</span> <span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">""</span>
res &= ch
<span style="color: #008080;">if</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;">=</span><span style="color: #008000;">'\"'</span> <span style="color: #008080;">then</span>
while 1 do
<span style="color: #000000;">res</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">ch</span>
sidx += 1
<span style="color: #008080;">while</span> <span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
ch = s[sidx]
<span style="color: #000000;">sidx</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
res &= ch
<span style="color: #000000;">ch</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">]</span>
if ch='\\' then
<span style="color: #000000;">res</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">ch</span>
sidx += 1
<span style="color: #008080;">if</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;">=</span><span style="color: #008000;">'\\'</span> <span style="color: #008080;">then</span>
ch = s[sidx]
<span style="color: #000000;">sidx</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
res &= ch
<span style="color: #000000;">ch</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">]</span>
elsif ch='\"' then
<span style="color: #000000;">res</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">ch</span>
sidx += 1
<span style="color: #008080;">elsif</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;">=</span><span style="color: #008000;">'\"'</span> <span style="color: #008080;">then</span>
exit
<span style="color: #000000;">sidx</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
end if
<span style="color: #008080;">exit</span>
end while
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
else
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
integer asnumber = (ch>='0' and ch<='9')
<span style="color: #008080;">else</span>
while not find(ch,") \t\r\n") do
<span style="color: #004080;">integer</span> <span style="color: #000000;">asnumber</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">ch</span><span style="color: #0000FF;">>=</span><span style="color: #008000;">'0'</span> <span style="color: #008080;">and</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;"><=</span><span style="color: #008000;">'9'</span><span style="color: #0000FF;">)</span>
res &= ch
<span style="color: #008080;">while</span> <span style="color: #008080;">not</span> <span style="color: #7060A8;">find</span><span style="color: #0000FF;">(</span><span style="color: #000000;">ch</span><span style="color: #0000FF;">,{</span><span style="color: #008000;">')'</span><span style="color: #0000FF;">,</span><span style="color: #008000;">' '</span><span style="color: #0000FF;">,</span><span style="color: #008000;">'\t'</span><span style="color: #0000FF;">,</span><span style="color: #008000;">'\r'</span><span style="color: #0000FF;">,</span><span style="color: #008000;">'\n'</span><span style="color: #0000FF;">})</span> <span style="color: #008080;">do</span>
sidx += 1
<span style="color: #000000;">res</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">ch</span>
if sidx>length(s) then exit end if
<span style="color: #000000;">sidx</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
ch = s[sidx]
<span style="color: #008080;">if</span> <span style="color: #000000;">sidx</span><span style="color: #0000FF;">></span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
end while
<span style="color: #000000;">ch</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">]</span>
if asnumber then
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
sequence scanres = scanf(res,"%f")
<span style="color: #008080;">if</span> <span style="color: #000000;">asnumber</span> <span style="color: #008080;">then</span>
if length(scanres)=1 then return {scanres[1][1],sidx} end if
<span style="color: #004080;">sequence</span> <span style="color: #000000;">scanres</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">scanf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">res</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%f"</span><span style="color: #0000FF;">)</span>
-- error? (failed to parse number)
<span style="color: #008080;">if</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">scanres</span><span style="color: #0000FF;">)=</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span> <span style="color: #008080;">return</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">scanres</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">][</span><span style="color: #000000;">1</span><span style="color: #0000FF;">],</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">}</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
end if
<span style="color: #000080;font-style:italic;">-- error? (failed to parse number)</span>
end if
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
return {res,sidx}
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
end function
<span style="color: #008080;">return</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">res</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">}</span>
 
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
function parse_s_expr(string s, integer sidx)
integer ch = s[sidx]
<span style="color: #008080;">function</span> <span style="color: #000000;">parse_s_expr</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">sidx</span><span style="color: #0000FF;">)</span>
sequence res = {}
<span style="color: #004080;">integer</span> <span style="color: #000000;">ch</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">]</span>
object element
<span style="color: #004080;">sequence</span> <span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>
if ch!='(' then ?9/0 end if
<span style="color: #004080;">object</span> <span style="color: #000000;">element</span>
sidx += 1
<span style="color: #008080;">if</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;">!=</span><span style="color: #008000;">'('</span> <span style="color: #008080;">then</span> <span style="color: #0000FF;">?</span><span style="color: #000000;">9</span><span style="color: #0000FF;">/</span><span style="color: #000000;">0</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
while 1 do
<span style="color: #000000;">sidx</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
sidx = skip_spaces(s,sidx)
<span style="color: #008080;">while</span> <span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
-- error? (if past end of string/missing ')')
<span style="color: #000000;">sidx</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">skip_spaces</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">)</span>
ch = s[sidx]
<span style="color: #000080;font-style:italic;">-- error? (if past end of string/missing ')')</span>
if ch=')' then exit end if
<span style="color: #000000;">ch</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">]</span>
if ch='(' then
<span style="color: #008080;">if</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;">=</span><span style="color: #008000;">')'</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
{element,sidx} = parse_s_expr(s,sidx)
<span style="color: #008080;">if</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;">=</span><span style="color: #008000;">'('</span> <span style="color: #008080;">then</span>
else
<span style="color: #0000FF;">{</span><span style="color: #000000;">element</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">parse_s_expr</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">)</span>
{element,sidx} = get_term(s,sidx)
<span style="color: #008080;">else</span>
end if
<span style="color: #0000FF;">{</span><span style="color: #000000;">element</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">get_term</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">)</span>
res = append(res,element)
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
end while
<span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">append</span><span style="color: #0000FF;">(</span><span style="color: #000000;">res</span><span style="color: #0000FF;">,</span><span style="color: #000000;">element</span><span style="color: #0000FF;">)</span>
sidx = skip_spaces(s,sidx+1)
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
return {res,sidx}
<span style="color: #000000;">sidx</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">skip_spaces</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
end function
<span style="color: #008080;">return</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">res</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">}</span>
 
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
sequence s_expr
integer sidx
<span style="color: #004080;">sequence</span> <span style="color: #000000;">s_expr</span>
{s_expr,sidx} = parse_s_expr(s_expr_str,1)
<span style="color: #004080;">integer</span> <span style="color: #000000;">sidx</span>
if sidx<=length(s_expr_str) then
<span style="color: #0000FF;">{</span><span style="color: #000000;">s_expr</span><span style="color: #0000FF;">,</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">parse_s_expr</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s_expr_str</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
printf(1,"incomplete parse(\"%s\")\n",{s_expr_str[sidx..$]})
<span style="color: #008080;">if</span> <span style="color: #000000;">sidx</span><span style="color: #0000FF;"><=</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s_expr_str</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span>
end if
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"incomplete parse(\"%s\")\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">s_expr_str</span><span style="color: #0000FF;">[</span><span style="color: #000000;">sidx</span><span style="color: #0000FF;">..$]})</span>
 
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
puts(1,"\nThe string:\n")
?s_expr_str
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"\nThe string:\n"</span><span style="color: #0000FF;">)</span>
 
<span style="color: #0000FF;">?</span><span style="color: #000000;">s_expr_str</span>
puts(1,"\nDefault pretty printing:\n")
--?s_expr
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"\nDefault pretty printing:\n"</span><span style="color: #0000FF;">)</span>
pp(s_expr)
<span style="color: #000080;font-style:italic;">--?s_expr</span>
 
<span style="color: #7060A8;">pp</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s_expr</span><span style="color: #0000FF;">)</span>
puts(1,"\nBespoke pretty printing:\n")
--ppEx(s_expr,{pp_Nest,1,pp_StrFmt,-1,pp_IntCh,false,pp_Brkt,"()"})
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"\nBespoke pretty printing:\n"</span><span style="color: #0000FF;">)</span>
ppEx(s_expr,{pp_Nest,4,pp_StrFmt,-1,pp_IntCh,false,pp_Brkt,"()"})</lang>
<span style="color: #000080;font-style:italic;">--ppEx(s_expr,{pp_Nest,1,pp_StrFmt,-1,pp_IntCh,false,pp_Brkt,"()"})</span>
<span style="color: #7060A8;">ppEx</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s_expr</span><span style="color: #0000FF;">,{</span><span style="color: #004600;">pp_Nest</span><span style="color: #0000FF;">,</span><span style="color: #000000;">4</span><span style="color: #0000FF;">,</span><span style="color: #004600;">pp_StrFmt</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #004600;">pp_IntCh</span><span style="color: #0000FF;">,</span><span style="color: #004600;">false</span><span style="color: #0000FF;">,</span><span style="color: #004600;">pp_Brkt</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"()"</span><span style="color: #0000FF;">})</span>
<!--</lang>-->
{{out}}
<pre>
Petelomax
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