Questions about built-in/custom parsers or parsing techniques.
10
votes
1answer
111 views
Lexical scanning and parsing in a toy language
I'm trying to do lexical scanning and parsing in a toy language. One with just functions (of the form $f(a,\,b,\,c,\,...)$, ended with semicolons) and special tokens (such as ...
2
votes
0answers
33 views
Confusing behavior for GrammarRules and GrammarApply
I have been experimenting with GrammarRules in an attempt to create a parser for text downloaded from the web. I have been using Interpreter to help understand the behavior of GrammarApply. Here is a ...
11
votes
1answer
94 views
Precedence of cell group tokens over package's expressions
Bug introduced in V10.4 or earlier and persisting through V11.3
[CASE:4072996]
...
9
votes
4answers
904 views
How to convert a string having nested parentheses into an expression?
I am a Wolfram Language/Mathematica beginner and trying to convert STEP ISO10303 commands into geometrical regions.
A simple command looks like
...
5
votes
1answer
159 views
How to determine if RHS of first order ODE is separable or linear or neither? Parsing problem
Introduction
This is really a parsing question. But the context is that
given the right side of first order ode, I want to automatically
determine the class of the RHS. It can be either separable, ...
0
votes
0answers
24 views
Parsing Module[…] creates additional Temporary symbols
Why this happens?
?? x$
Hold[Module[{x}, x]]
?? x$
17
votes
1answer
326 views
Is building an event-based parser possible/reasonable in Mathematica (WL)?
Too long? Go to Problems section
Background
I like to learn by doing small, sometimes artificial, projects. Among other things I had 'parsers', and 'stream methods / streams in MMA' on my to learn ...
7
votes
2answers
215 views
Getting the front sign of an expression. Positive or negative for formatting only
This is for the purpose of generating a string (actually it will Latex string, but that is not important).
I need to generate string as
...
5
votes
1answer
52 views
Can we make preread replacements in an *.m* file before being run?
This the second question of (152743), the preamble of which is reproduced here:
Those who don't have/prefer the front end of Mathematica will either use a plain ASCII editor to write a script in an ...
5
votes
1answer
44 views
Can we make new definitions for InputForm in packages?
Those who don't have/prefer the front end of Mathematica will either use a plain ASCII editor to write a script in an .m file or just use Mathematica directly from ...
1
vote
0answers
49 views
Scraping XML Paragraphs with URLs
I've been working on scraping an article from CNBC. The link is here
I want to scrape the main body, and the code I have so far is this:
...
1
vote
1answer
79 views
Ugly Gaussian symbolic integration, how to extract coefficients and exponent argument?
I have a very ugly function with 157 terms that I want to integrate over three variables. Each term is a Gaussian integral in those variables multiplied by a polynomial in the variables. However, in ...
3
votes
1answer
234 views
Pulling Out Values from JSON Association
Having a bit of trouble pulling a value out of a JSON Association here. I am scraping this website: http://www.msn.com/en-us/money/stockdetails/history/fi-126.1.BY.NYS
I want to scrape the closing ...
0
votes
0answers
211 views
HTTP Status Code 403
I'm working with some scraping and have run into a bit of a problem. The website I am scraping is this: https://seekingalpha.com/symbol/CRM/stocktalks
I am essentially trying to scrape the "stock ...
1
vote
1answer
49 views
Extracting Certain Areas of JSON
I've been working with some web scraping and have run into a wall. The website I'm working with is this: https://seekingalpha.com/symbol/TWLO/stocktalks
I am trying to scrape all of the "stock talks" ...
2
votes
1answer
155 views
Parsing and Extracting XML Content
I've run into a little question while trying to parse XML. This seems like a rather simple task, but for the life of me I cannot figure it out. I pull up the XML of the website using the following ...
2
votes
2answers
223 views
Parse command line arguments
I have been trying to parse command line arguments.
There are a couple of types of options.
1. Mandatory
2. Optional
3. Alternative
There are built-in/3rd ...
6
votes
0answers
78 views
Infix non-ASCII operator needs a space to be parsed correctly in a script
Bug introduced in 9.0 or earlier and persisting through 11.1
First off:
...
5
votes
1answer
627 views
3
votes
0answers
32 views
Unexpected behaviour with WordSeparators and Read [duplicate]
I am confused about how Read separates elements.
The following all work fine:
...
4
votes
1answer
145 views
Context inside Do[…]-loop
Consider the following code:
Begin["mycontext`"];
myvar = 7;
Print[Context[]];
Print[Context[myvar]];
End[];
with the output
mycontext`
mycontext`
Now ...
3
votes
2answers
404 views
Reading a text file and parsing only the text between two delimiters
How are you?
I'm a chemist with almost no experience with Mathematica, but I'm thinking of using it as a tool for my Ph.D in Computational Chemistry. My Quantum Chemistry software (ORCA) generates a ...
1
vote
2answers
136 views
How is a single tilde parsed?
How is a~b parsed and evaluated? I would expect an error, but it goes through without any complaints, yielding no apparent output. At first I thought it evaluated ...
4
votes
1answer
52 views
How do I import a Dataset that contains lists?
The very first example in the Dataset documentation is the following:
...
3
votes
1answer
80 views
How to use MakeExpression for single characters
Here is code that I thought would make the front end parse f as BigFunction:
...
8
votes
4answers
755 views
How to get the longest bracket pairs from a string
In C#, we can use regular expression to do some balancing groups, like we can get
{<aa <bbb> <bbb> aa>, <<dfa>a>}
from
...
18
votes
4answers
807 views
Is it important that the front-end has a built-in parser?
The Notebook interface has a parser that seems aware of all operator-precedences, allowing us to step through the expressions (rather: Box-) hierarchy with Ctrl+.
This is extremely convenient, saving ...
6
votes
1answer
64 views
Can Read[] apply a custom function automatically to the read values?
Read[stream, Number] will return a single read number. We can use a number of standard, documented types instead of Number, ...
2
votes
0answers
91 views
SymbolicC/SymbolicCUDAFunction generating C/C++ parser?
I wish to do some program transformation and analysis.
Is there any package that generates SymbolicC expressions from C code?
In a sense I'm looking for the ...
3
votes
1answer
80 views
How to speed up accidental large output?
From time to time I accidentally let large expressions like RandomReal[1., {10^5, 10, 10}] reach the front end. The computation of the result is quite fast (...
9
votes
1answer
170 views
Why is this syntax for patterns with Optional values not supported?
I want to express Optional[PatternTest[Pattern[a,Blank[]],t],1] concisely.
a : _?t : 1 is not quite this but works: ...
4
votes
0answers
77 views
Weird bug with Esc, string, and underscore? [closed]
There seems to be a bug with esc key, strings, and underscores.
For instance, see the following code:
a = f["1_2"];
If an esc character is typed anywhere ...
1
vote
2answers
86 views
Use cases to exclude data values over a certain threshold
I am trying to parse data output from a fluorometer. My output is basically signal intensity over time. So I have a list of 2 value lists with the first value time and the second signal e.g., ...
8
votes
2answers
232 views
FullForm with context for each symbol?
FullForm strips the context for any symbol that can be found on the Append[$ContextPath, $Context]: ...
0
votes
1answer
161 views
How to read a part of huge matrix saved in a TXT file as single expression?
I saved a huge matrix of numbers with dimensions {400, 4001, 2} using Put and got a TXT file formatted in the following way:
<...
5
votes
1answer
190 views
How to get “one Cell - one line” code format inside of NB files?
The PageWidth option controls the way the Cell's content is displayed, not the manner it's written in a ...
21
votes
2answers
564 views
Shell Emulation inside Mathematica
I am trying to create a Mathematica/shell syntax hybrid.
I would like the following command
wget -qO- "http://google.com/space line
break\"" $var
to be ...
4
votes
1answer
212 views
When does Mathematica insert parenthesis into expression?
expr//HoldForm usually returns identical expressions as input, but sometimes parenthesis are inserted. I tried to interpret this behavior as an attempt to eliminate ...
13
votes
2answers
762 views
How to parse a clojure expression?
Clojure is a lisp-like language that runs on JVM and in Javascript. I just started learning it and I'm building a simple parser with Mathematica to understand and visualize it.
Like other lisps every ...
3
votes
1answer
75 views
Skipping commented in a stream from OpenRead
Is there a solution to skip comments in text files that are imported with OpenRead? I know there are solutions for Importand <...
3
votes
1answer
85 views
`ReadString` and `StreamPosition` behaving strangely with custom terminators
I've stumbled on a strange behavior while trying to use custom terminators for ReadString.
When I use a simple String as the ...
4
votes
3answers
1k views
Importing CSV with multiline text fields
Bug introduced in 8 or earlier and fixed in 11.2.0
Here is a valid CSV:
a1,b1,c1,d1,"e1
e1
e1"
a2,b2,"c2
c2
c2",d2,e2
It has two rows and five columns, and ...
4
votes
1answer
190 views
How to get the list of links in a Wikipedia article in order of appearance
I can get a list of links in a Wikipedia article using WikipediaData:
...
2
votes
0answers
74 views
Where do the radicals end?
In an early iteration of this question on the Mathematics SE, the radicals weren't properly formatted, so they only had the √ symbol with no indication of which terms were supposed to be ...
4
votes
2answers
172 views
Parsing tab delimited file
Problem Description
I have my data arranged in a tab delimited file and I'm trying to parse/access certain parts of it.
As an example, I'd like to extract the number of points and the sampling ...
0
votes
0answers
470 views
How to prevent space trimming when importing HTML with ImportString?
I am importing a HTML-formatted string with
ImportString[string, "HTML"]
to properly parse all HTML-escaped characters like ...
26
votes
0answers
419 views
Front end goes wild with named slots
Bug introduced in 10 and persisting through 11.2.0
Assume the following simple expression
{#"Test"}&
Now go in front of the ...
15
votes
0answers
186 views
Why does the Ver. 10.0 FrontEnd lose matching of parentheses when we insert quotations?
I am running Mathematica 10.0.1 on a four-year old iMac running OS 10.6.8. The following irritating behavior occurs regularly: I have a list with parentheses, and later on I need to add something to ...
0
votes
2answers
123 views
Extracting part of an expression
My goal is to solve $(\alpha - \dfrac{1}{\alpha}) - (\beta- \dfrac{1}{\beta}) = \dfrac 1 n$ where $\alpha$ and $\beta$ are rational and $n$ is a positive integer. Towards finding a particular solution,...
4
votes
1answer
218 views
Parsing string with nested information
I am trying to parse a string, but I have no idea how to solve the following problem
...
