Why can't my yacc rule reduce here? - c

I am using YACC to do my compiler homework project. I found that my program could not get the syntax tree. So I printed it all out to see what is happening. According to my result, it seems that ClassDecl does not reduce to ClassDeclList here. But I can't understand why... can anyone help me out?
The sample input is:
program ex11;
class ab {
}
It printed out as:
programXXXX ex11ID
semicon abID
RBRACEnum
ClassBody ClassDecl ClassDecl1 Error!
The first three lines are messages I printed from my LEX file, to ensure that the characters are recognized correctly.
According to the information, the parser successfully reduces {} to ClassBody and class ab {} to ClassDecl. And then it does not reduce to ClassDeclList, is it because I am writing a left recursive grammar here?
This is the part of my YACC rule base for the inference:
Program: PROGRAMnum IDnum SEMInum ClassDeclList
{printf("program"); $$ = MakeTree(ProgramOp,$4, MakeLeaf(IDNode,$2)); printtree($$,0);};
ClassDeclList: ClassDecl
{printf("ClassDeclList1");$$ = MakeTree(ClassOp,NullExp(),$1); printf("ClassDeclListend");};
|ClassDecl ClassDeclList
{printf("ClassDeclList2");$$ = MakeTree(ClassOp,$2,$1); printf("ClassDeclList");};
ClassDecl: CLASSnum IDnum ClassBody
{printf("ClassDecl");$$=MakeTree(ClassDefOp,$3,MakeLeaf(IDNode,$2)); printf("ClassDecl1");};

Have you tried
| ClassDeclList ClassDecl
instead of
| ClassDecl ClassDeclList
?
I remember this fixing many problems when I used to use CUP.

Related

how do I filter my values using an array?

I am trying to sift through some free text answers on geographical locations. As one of the steps, I want to check if the answer is any of the 290 municipalities in my country. As 290 entries would make my code cumbersome/hard to read I try saving them in an array, like below:
Data resorTEST;
keep R_res_ort_namn R_res_ort_txt R_kom_lan R_kommun;
set resor1TEST resor2TEST resor3TEST;
R_res_ort_namn=strip(lowcase(R_res_ort_namn));
R_res_ort_txt=strip(lowcase(R_res_ort_txt));
R_kom_lan=strip(lowcase(R_kom_lan));
array kommuner{290} $ ("upplands väsby" "vallentuna" "österåker" "värmdö"
"järfälla" "ekerö" "huddinge" "botkyrka" "salem"
"haninge" "tyresö" "upplands-bro" "nykvarn" "täby"
"danderyd" "sollentuna" "stockholm" "södertälje" "nacka" "sundbyberg"
"solna" "lidingö" "vaxholm" "norrtälje" "sigtuna" "nynäshamn"
"håbo" "älvkarleby" "knivsta" "heby" "tierp" "uppsala"
"enköping" "östhammar" "vingåker" "gnesta" "nyköping" "oxelösund" "flen"
"katrineholm" "eskilstuna" "strängnäs" "trosa" "ödeshög" "ydre"
"kinda" "boxholm" "åtvidaberg" "finspång" "valdemarsvik" "linköping"
"norrköping" "söderköping" "motala" "vadstena" "mjölby" "aneby"
"gnosjö" "mullsjö" "habo" "gislaved" "vaggeryd" "jönköping"
"nässjö" "värnamo" "sävsjö" "vetlanda" "eksjö" "tranås"
"uppvidinge" "lessebo" "tingsryd" "alvesta" "älmhult" "markaryd"
"växjö" "ljungby" "högsby" "torsås" "mörbylånga" "hultsfred"
"mönsterås" "emmaboda" "kalmar" "nybro" "oskarshamn" "västervik"
"vimmerby" "borgholm" "gotland" "olofström" "karlskrona" "ronneby"
"karlshamn" "sölvesborg" "svalöv" "staffanstorp" "burlöv" "vellinge"
"östra göinge" "örkelljunga" "bjuv" "kävlinge" "lomma" "svedala"
"skurup" "sjöbo" "hörby" "höör" "tomelilla" "bromölla"
"osby" "perstorp" "klippan" "åstorp" "båstad" "malmö"
"lund" "landskrona" "helsingborg" "höganäs" "eslöv" "ystad"
"trelleborg" "kristianstad" "simrishamn" "ängelholm" "hässleholm" "hylte"
"halmstad" "laholm" "falkenberg" "varberg" "kungsbacka" "härryda"
"partille" "öckerö" "stenungsund" "tjörn" "orust" "sotenäs"
"munkedal" "tanum" "dals-ed" "färgelanda" "ale" "lerum"
"vårgårda" "bollebygd" "grästorp" "essunga" "karlsborg" "gullspång"
"tranemo" "bengtsfors" "mellerud" "lilla edet" "mark" "svenljunga"
"herrljunga" "vara" "götene" "tibro" "töreboda" "göteborg"
"mölndal" "kungälv" "lysekil" "uddevalla" "strömstad" "vänersborg"
"trollhättan" "alingsås" "borås" "ulricehamn" "åmål" "mariestad"
"lidköping" "skara" "skövde" "hjo" "tidaholm" "falköping"
"kil" "eda" "torsby" "storfors" "hammarö" "munkfors"
"forshaga" "grums" "årjäng" "sunne" "karlstad" "kristinehamn"
"filipstad" "hagfors" "arvika" "säffle" "lekeberg" "laxå"
"hallsberg" "degerfors" "hällefors" "ljusnarsberg" "örebro" "kumla"
"askersund" "karlskoga" "nora" "lindesberg" "skinnskatteberg" "surahammar"
"kungsör" "hallstahammar" "norberg" "västerås" "sala" "fagersta"
"köping" "arboga" "vansbro" "malung-sälen" "gagnef" "leksand"
"rättvik" "orsa" "älvdalen" "smedjebacken" "mora" "falun"
"borlänge" "säter" "hedemora" "avesta" "ludvika" "ockelbo"
"hofors" "ovanåker" "nordanstig" "ljusdal" "gävle" "sandviken"
"söderhamn" "bollnäs" "hudiksvall" "ånge" "timrå" "härnösand"
"sundsvall" "kramfors" "sollefteå" "örnsköldsvik" "ragunda" "bräcke"
"krokom" "strömsund" "åre" "berg" "härjedalen" "östersund"
"nordmaling" "bjurholm" "vindeln" "robertsfors" "norsjö" "malå"
"storuman" "sorsele" "dorotea" "vännäs" "vilhelmina" "åsele"
"umeå" "lycksele" "skellefteå" "arvidsjaur" "arjeplog" "jokkmokk"
"överkalix" "kalix" "övertorneå" "pajala" "gällivare" "älvsbyn"
"luleå" "piteå" "boden" "haparanda" "kiruna");
/*if not missing(R_res_ort_namn) then R_kommun=prxchange("s/^.*-(.* kommun)/$1/",1,R_res_ort_namn);
else if prxmatch("/^.*([a-zA-Z]*? kommun).*$/",R_res_ort_txt) then R_kommun=prxchange("s/^.*?([a-zA-Z]*? kommun).*$/$1/",-1,R_res_ort_txt);
else if prxmatch("/^.*([a-zA-Z]*? kommun).*$/",R_kom_lan) then R_kommun=prxchange("s/^.*?([a-zA-Z]*? kommun).*$/$1/",-1,R_kom_lan);
else */if R_res_ort_txt in kommuner then R_kommun=R_res_ort_txt;
run;
However, for some reason this does not seem to work for all of the municipalities. The municipality of "uppsala" works for instance, but not the municipality of "ängelholm".
I have tried stripping the variables of whitespace and converting everything to lowercase. What am I doing wrong?
Additional info:
For some reason it does work flawlessly if I skip the array and just copy-paste the exact same list of municipality names into a parenthesis following the in-operator. I would however need to repeat this step 5-6 times and this solution would make my code quite cumbersome.
You are defining the ARRAY
Array kommuner{290} $
with character length 8. See what happens when you fix that.

What method am I not using right?

I'm new to Julia and currently trying to run the following code:
Using DelimitedFiles
M=readdlm(data)
ts,A=M[:,1],M[:,2:end]
(nsweeps,N)=size(A)
dx=0.01;
x=[minimum(collect(A)):dx:maximum(collect(A))];
bx=[x-dx/2,x[end]+dx/2];
But, when I try to run the last line of code, it gives me the following error:
MethodError: no method
matching(::Array{StepRangeLen{Float64,Base.TwicePrecision
{Float64},Base.TwicePrecision{Float64}},1}, ::Float64)
Closest candidates are:
-(!Matched::BigFloat, ::Union{Float16, Float32, Float64}) at
mpfr.jl:437
-(!Matched::Complex{Bool}, ::Real) at complex.jl:307
-(!Matched::Missing, ::Number) at missing.jl:115
Can you please help me? Also, the data I'm using it's
30×6 Array{Float64,2}
UPDATE here's the whole function I'm trying to run is the following:
function mymain(filename,nsamples)
start_time=time()
M=readdlm(filename)
ts,A=M[:,1],M[:,2:end]
(nsweeps,N)=size(A)
dx=0.01;
x=[minimum(collect(A)):dx:maximum(collect(A))];
bx=[x-dx/2,x[end]+dx/2];
(bx,hA)=hist(A[:],bx);
f1=figure()
subplot(2,1,1); plot(ts,A,"-o"); xlabel("Time [ms]"); ylabel("Amps
[mV]");
subplot(2,1,2); plot(x,hA,"-"); xlabel("Amps [mV]");
ylabel("Density");draw()
nparams=8
Sx=Array(ASCIIString,1,nparams)
Rx=zeros(2,nparams)
nx=zeros(Int,1,nparams)
Sx[1,1]="p"; Rx[1:2,1]=[0.02,0.98]; nx[1]=49
Sx[1,2]="n"; Rx[1:2,2]=[1,20]; nx[2]=20
Sx[1,3]="tD"; Rx[1:2,3]=[50,200]; nx[3]=46
Sx[1,4]="a"; Rx[1:2,4]=[0.05,0.5]; nx[4]=46
Sx[1,5]="siga"; Rx[1:2,5]=[0.01,0.2]; nx[5]=39
Sx[1,6]="sigb"; Rx[1:2,6]=[0.01,0.1]; nx[6]=19
Sx[1,7]="tauf"; Rx[1:2,7]=[50,200]; nx[7]=46
Sx[1,8]="u1"; Rx[1:2,8]=Rx[1:2,1]; nx[8]=nx[1]
x=zeros(maximum(nx),nparams)
p=zeros(maximum(nx),nparams)
dx=zeros(1,nparams)
for j=1:nparams
x[1:nx[j],j]=linspace(Rx[1,j],Rx[2,j],nx[j])'
dx[j]=x[2,j]-x[1,j]
end
S=zeros(Int,nsamples,nparams)
sold=zeros(Int,1,nparams)
for j=1:nparams
sold[j]=rand(1:nx[j])
end
while x[sold[4],4]<=x[sold[5],5]
sold[4]=rand(1:nx[4])
sold[5]=rand(1:nx[5])
end
while x[sold[8],8]<=x[sold[1],1]
sold[1]=rand(1:nx[1])
sold[8]=rand(1:nx[8])
end
xold=zeros(1,nparams)
xnew=zeros(1,nparams)
for j=1:nparams
xold[j]=x[sold[j],j]
end
llold=myloglikelihood(xold,ts,A)
for k=1:nsamples
snew=sold+rand(-1:1,1,nparams)
if all(ones(1,nparams).<=snew.<=nx)
allowed2=x[snew[4],4]>x[snew[5],5]
allowed3=x[snew[8],8]>x[snew[1],1]
if allowed2&allowed3
for j=1:nparams
xnew[j]=x[snew[j],j]
end
llnew=myloglikelihood(xnew,ts,A)
if rand()<exp(llnew-llold)
sold,llold=snew,llnew
end
end
end
S[k,:]=sold
end
for k=1:nsamples
for j=1:nparams
p[S[k,j],j]+=1/(nsamples*dx[j])
end
end
f2=figure()
for j=1:nparams
subplot(2,4,j)
plot(x[1:nx[j],j],p[1:nx[j],j]);
xlabel(Sx[j])
end
diff_time=time()-start_time;
println("Total runtime
",round(diff_time,3),"s=",round(diff_time/60,1),"mins." );
return S
end
This goes in line with some other functions, but as you can see, this is the main function, so I really can't move forward without first runnning this one.
It isn't clear what outcome you are hoping for here. So I'll just give some pointers that hopefully help.
First, in this line:
x=[minimum(collect(A)):dx:maximum(collect(A))];
the calls to collect are redundant. Also, I suspect you are trying to construct a StepRangeLen, but by putting it in [] you actually are getting a Vector{StepRangeLen}. I think what you want in this line is actually this:
x=minimum(A):dx:maximum(A);
Second, in this line:
bx=[x-dx/2,x[end]+dx/2];
note that dx/2 is a Float64 while x is a StepRangeLen. This is important because the latter is a collection so if you want to perform this operation element-wise across the collection you need to broadcast, that is, x .- dx/2. Note, I suspect you may not be on the latest version of Julia, because when I run this the error message actually tells me explicitly I need to broadcast. Anyway, in contrast, x[end]+dx/2 is fine and does not need to be broadcast because x[end] is Float64. So I think you want:
bx=[x .- dx/2, x[end] + dx/2];
Having said that, it isn't clear to me why you want this bx, which is why I said at the start I'm not sure what outcome you were hoping for.

Error: Can't Assign Function Call / Don't want to

It's friday and I'm tired and my brain obvs doesn't want to find this answer. Please help.
I want to assign the value to an array. It works in subsequent lines but not in one particular line, even though syntax seems the same to me? It seems to think I'm calling a function??
for entry in PROJECT:
i = i + 1
#A
if entry.startswith("A") :
ProjectA(i) = entry
#B
elif entry.startswith("B"):
ProjectB(i)= entry
#C
elif entry.startswith("C") :
ProjectC(i) = entry
# and Programme
elif entry.startswith("D") :
ProjectD(i) = entry
I'm told the problem is the last line: "ProjectD(i) = entry". Which to me seems like a replica of "ProjectC(i) = entry"
ProjectA(i) looks like you are calling a function; ProjectA[i] looks like an array element.

How can I read this line in the C language

I am writing in C and I am trying to read this line:
phillip.allen#enron.com -> tim.belden#enron.com at 989883540
I want 4 separate strings:
sender_username: phillip.allen
sender_hostname: enron.com
receiver_username: tim.belden
receiver_hostname: enron.c
I want to get rid of the "at 989883540" part of the text.
I am using this conversion:
"%49[^# ]#%49s -> %49[^# ]#%49s"
I seem to get the sender username and hostname, so the first part of the email before the -> symbol, but I cannot read the receiver part of tim.belden part.
Replacing %49s with %49[^ ] should do the trick:
"%49[^#]#%49[^ ] -> %49[^#]#%49[^ ]"
Here is a demo on ideone.

ANTLR3 C Target - parser return 'misses' out root element

I'm trying to use the ANTLR3 C Target to make sense of an AST, but am running into some difficulties.
I have a simple SQL-like grammar file:
grammar sql;
options
{
language = C;
output=AST;
ASTLabelType=pANTLR3_BASE_TREE;
}
sql : VERB fields;
fields : FIELD (',' FIELD)*;
VERB : 'SELECT' | 'UPDATE' | 'INSERT';
FIELD : CHAR+;
fragment
CHAR : 'a'..'z';
and this works as expected within ANTLRWorks.
In my C code I have:
const char pInput[] = "SELECT one,two,three";
pANTLR3_INPUT_STREAM pNewStrm = antlr3NewAsciiStringInPlaceStream((pANTLR3_UINT8) pInput,sizeof(pInput),NULL);
psqlLexer lex = sqlLexerNew (pNewStrm);
pANTLR3_COMMON_TOKEN_STREAM tstream = antlr3CommonTokenStreamSourceNew(ANTLR3_SIZE_HINT,
TOKENSOURCE(lex));
psqlParser ps = sqlParserNew( tstream );
sqlParser_sql_return ret = ps->sql(ps);
pANTLR3_BASE_TREE pTree = ret.tree;
cout << "Tree: " << pTree->toStringTree(pTree)->chars << endl;
ParseSubTree(0,pTree);
This outputs a flat tree structure when you use ->getChildCount and ->children->get to recurse through the tree.
void ParseSubTree(int level,pANTLR3_BASE_TREE pTree)
{
ANTLR3_UINT32 childcount = pTree->getChildCount(pTree);
for (int i=0;i<childcount;i++)
{
pANTLR3_BASE_TREE pChild = (pANTLR3_BASE_TREE) pTree->children->get(pTree->children,i);
for (int j=0;j<level;j++)
{
std::cout << " - ";
}
std::cout <<
pChild->getText(pChild)->chars <<
std::endl;
int f=pChild->getChildCount(pChild);
if (f>0)
{
ParseSubTree(level+1,pChild);
}
}
}
Program output:
Tree: SELECT one , two , three
SELECT
one
,
two
,
three
Now, if I alter the grammar file:
sql : VERB ^fields;
.. the call to ParseSubTree only displays the child nodes of fields.
Program output:
Tree: (SELECT one , two , three)
one
,
two
,
three
My question is: why, in the second case, is Antlr just give the child nodes? (in effect missing out the SELECT token)
I'd be very grateful if anybody can give me any pointers for making sense of the tree returned by Antlr.
Useful Information:
AntlrWorks 1.4.2,
Antlr C Target 3.3,
MSVC 10
Placing output=AST; in the options section will not produce an actual AST, it only causes ANTLR to create CommonTree tokens instead of CommonTokens (or, in your case, the equivalent C structs).
If you use output=AST;, the next step is to put tree operators, or rewrite rules inside your parser rules that give shape to your AST.
See this previous Q&A to find out how to create a proper AST.
For example, the following grammar (with rewrite rules):
options {
output=AST;
// ...
}
sql // make VERB the root
: VERB fields -> ^(VERB fields)
;
fields // omit the comma's from the AST
: FIELD (',' FIELD)* -> FIELD+
;
VERB : 'SELECT' | 'UPDATE' | 'INSERT';
FIELD : CHAR+;
SPACE : ' ' {$channel=HIDDEN;};
fragment CHAR : 'a'..'z';
will parse the following input:
UPDATE field, foo , bar
into the following AST:
I think it is important that you realize that the tree you see in Antrlworks is not the AST. The ".tree" in your code is the AST but may look different from what you expect. In order to create the AST, you need to specify the nodes using the ^ symbol in strategic places using rewrite rules.
You can read more here

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