Warum muss `\the` bei Ausgabe von higher level Komponenten-Extraktion eines Punktes gesetzt werden und bei lower level nicht?

Hi, ich habe nach einer Funktion zum Ermitteln der Einzelkomponenten (x,y) eines Punktes gesucht und bin bei Tex.SX fündig geworden. Im folgenden Beispiel habe ich zwei Varianten ausprobiert und habe ein Problem mit der zweiten (\getxyother higher level, da nur LaTeX).

Open in writeLaTeX

Code, hier editierbar zum Übersetzen:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
\documentclass{scrartcl}
\usepackage{tikz}
\makeatletter
\newcommand{\getxy}[3]{% 1: point, 2: x-dimen, 3: y-dimen
  \tikz@scan@one@point\pgfutil@firstofone#1\relax
  \edef#2{\the\pgf@x}%
  \edef#3{\the\pgf@y}%
}
\makeatother
\newcommand{\getxyother}[3]{% 1: point, 2: x-dimen, 3: y-dimen
    \newdimen{#2}
    \newdimen{#3}
    \coordinate (temp) at #1;
    \pgfextractx{#2}{\pgfpointanchor{temp}{center}}
    \pgfextracty{#3}{\pgfpointanchor{temp}{center}}
}
\begin{document}
\begin{tikzpicture}
    \coordinate (temp) at (3,2);
    \getxy{(temp)}{\x}{\y};
    \getxyother{(temp)}{\xother}{\yother};
    \draw (\x,\y) -- (\yother,\xother);
    \node[green] at (\x,\y) {\x\ : \y};
    \node[red] at (\yother,\xother) {\the\yother\ : \the\xother};
\end{tikzpicture}
\end{document}
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Warum muss bei der zweiten Variante \the bei textueller Ausgabe verwendet werden und bei der ersten nicht?

tikz

gefragt 10 Aug '14, 14:33

ErnstZ
611●14●28●33
Akzeptiert-Rate: 62%

bearbeitet 10 Aug '14, 14:37

Eine Antwort:

active answers älteste Antworten neueste Antworten Beliebteste Antworten

Was tut `\the`?

Es gibt verschiedene Arten von Tokens in TeX. Da sind einmal die Control Sequences die man über \def definiert. Dann gibt es noch die Register, wir beschränken uns hier auf Register vom Typ dimen. Ein solches Register alloziert man mittels \newdimen.

Sei der Token \getxy eine Control Sequence. Um TeX dazu zu bringen ihn zu expandieren, also seinen Replacement Text einzusetzen schreibt man im Dokument einfach

Open in writeLaTeX

Code, hier editierbar zum Übersetzen:

1
2
\def\getxy{...}
\getxy
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Bei Registern sieht das anders aus. Man kann nicht das Register an sich expandieren sondern nur seinen Wert setzen oder auslesen. Sei dazu \xother ein Register vom Typ dimen. Wir setzen den Wert mittels

Open in writeLaTeX

Code, hier editierbar zum Übersetzen:

1
2
3
\newdimen\xother
\xother=5pt
\xother1cm
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Das Gleichheitszeichen ist optional hilft aber der Lesbarkeit. Um nun den Wert des Registers zu erhalten benötigen wir eine Control Sequence die auf den Inhalt des Registers expandiert. Genau das tut \the.

Open in writeLaTeX

1
\the\xother
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Es dürfte offensichtlich sein, warum

Open in writeLaTeX

1
\xother
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

den Fehler ! Missing number, treated as zero. hervorruft.

Warum tut in TikZ beides?

Seien zwei Punkte definiert als

Open in writeLaTeX

Code, hier editierbar zum Übersetzen:

1
2
3
4
5
6
\def\x{55pt}
\def\y{86pt}
\newdimen\xother
\newdimen\yother
\xother=55pt
\yother=86pt
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Dies ist offensichtlich beides mal der gleiche Punkt. In TikZ kann ich nun Nodes an die Punkte setzen mittels

Open in writeLaTeX

Code, hier editierbar zum Übersetzen:

1
2
\node at (\x,\y) {...};
\node at (\xother,\yother) {...};
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Die Koordinaten werden gelesen mit etwas das so ähnlich ist wie

Open in writeLaTeX

Code, hier editierbar zum Übersetzen:

1
2
\pgf@x=#1
\pgf@y=#2
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

wobei \pgf@x und \pgf@y Register vom Typ dimen sind und #1 und #2 die x- und y-Koordinate des Punktes sind. Im Fall von \xother und \yother haben wir bereits zwei dimen-Register und die Zuweisung funktioniert ohne Probleme. Im Fall von \x und \y muss einmal expandiert werden aber dann stehen auch zwei Längen da, viz. der Replacement Text 55pt und 86pt, respektive.

Dein Code ohne `\the`

Ich habe übrigens keine Ahnung was Du mit high-level und low-level meinst.

Open in writeLaTeX

Code, hier editierbar zum Übersetzen:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
\documentclass{article}
\pagestyle{empty}
\usepackage{tikz}
\makeatletter
\newcommand{\getxy}[3]{% 1: point, 2: x-dimen, 3: y-dimen
  \tikz@scan@one@point\pgfutil@firstofone#1\relax
  \edef#2{\the\pgf@x}%
  \edef#3{\the\pgf@y}%
}
\makeatother
\newcommand{\getxyother}[3]{% 1: point, 2: x-dimen, 3: y-dimen
    \coordinate (temp) at #1;
    \pgfextractx{\dimen0}{\pgfpointanchor{temp}{center}}
    \edef#2{\the\dimen0}
    \pgfextracty{\dimen0}{\pgfpointanchor{temp}{center}}
    \edef#3{\the\dimen0}
}
\begin{document}
\begin{tikzpicture}
    \coordinate (temp) at (3,2);
    \getxy{(temp)}{\x}{\y};
    \getxyother{(temp)}{\xother}{\yother};
    \draw (\x,\y) -- (\yother,\xother);
    \node[green] at (\x,\y) {\x\ : \y};
    \node[red] at (\yother,\xother) {\yother\ : \xother};
\end{tikzpicture}
\end{document}
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Dein Code in Plain TeX

Open in writeLaTeX

Code, hier editierbar zum Übersetzen:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
\nopagenumbers
\input tikz
\catcode`\@=11
\def\getxy#1#2#3{% 1: point, 2: x-dimen, 3: y-dimen
  \tikz@scan@one@point\pgfutil@firstofone#1\relax
  \edef#2{\the\pgf@x}%
  \edef#3{\the\pgf@y}%
}
\catcode`\@=12
\def\getxyother#1#2#3{% 1: point, 2: x-dimen, 3: y-dimen
    \coordinate (temp) at #1;
    \pgfextractx{\dimen0}{\pgfpointanchor{temp}{center}}
    \edef#2{\the\dimen0}
    \pgfextracty{\dimen0}{\pgfpointanchor{temp}{center}}
    \edef#3{\the\dimen0}
}
\tikzpicture
    \coordinate (temp) at (3,2);
    \getxy{(temp)}{\x}{\y};
    \getxyother{(temp)}{\xother}{\yother};
    \draw (\x,\y) -- (\yother,\xother);
    \node[green] at (\x,\y) {\x\ : \y};
    \node[red] at (\yother,\xother) {\yother\ : \xother};
\endtikzpicture
\bye
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Permanenter link

beantwortet 10 Aug '14, 14:55

Henri
15.7k●13●39●43
Akzeptiert-Rate: 46%

bearbeitet 11 Aug '14, 10:05

Danke @Henri. Sehr schöne ausführliche Antwort. Vor allem die Erklärung, warum in TikZ beides geht.

Mit high und low level meinte ich, dass ersteres LaTeX-Bordmittel benutzt und zweiteres TeX-Bordmittel.

(10 Aug '14, 14:59) ErnstZ

@ErnstZ Ich glaube Du definierst den Unterschied darüber, dass \getxy private Makros mit @ im Namen verwendet (was nichts mit einem Unterschied zwischen Plain TeX und LaTeX zu tun hat). Das einzige was \getxy und \getxyother von einer Plain TeX Implementierung unterscheidet ist die Verwendung von \newcommand statt \def und \makeatletter statt \catcode`\@=11, der ganze Rest tut auch wunderbar in Plain TeX.

(11 Aug '14, 10:03) Henri

Deine Antwort

[Vorschau ausblenden]

Community Wiki:

Folgen dieser Frage

Per E-Mail:

Wenn sie sich anmelden, kommen Sie für alle Updates hier in Frage

Per RSS:

Antworten

Antworten und Kommentare

Frage-Themen:

tikz ×731

gestellte Frage: 10 Aug '14, 14:33

Frage wurde gesehen: 5,435 Mal

zuletzt geändert: 11 Aug '14, 10:05

Warum muss `\the` bei Ausgabe von higher level Komponenten-Extraktion eines Punktes gesetzt werden und bei lower level nicht?

Was tut \the?

Warum tut in TikZ beides?

Dein Code ohne \the

Dein Code in Plain TeX

Folgen dieser Frage

verwandte Fragen

Was tut `\the`?

Dein Code ohne `\the`