Template:Ifndef/doc

{{ifndef/doc}} is a compact variant of {{Qif}} for simple "if defined then void else do" statements with blank then part. It's the opposite of {{ifdef}}.

Usage

{{Ifndef/doc|value|result}} yields result  if value  is blank.

This simple template cannot be substituted, it's used to simplify the following equivalent but somewhat cryptic (names don't matter) code variants:

{{{2{{{1|}}}|}}}

{{{result{{{value|}}}|}}}

{{{then{{{test|}}}|}}}

Example

Code	Result
1 {{Ifndef/doc| |empty}}	1 {{ifndef/doc}} is a compact variant of {{Qif}} for simple "if defined then void else do" statements with blank then part. It's the opposite of {{ifdef}}. Usage {{Ifndef/doc|value|result}} yields result  if value  is blank. This simple template cannot be substituted, it's used to simplify the following equivalent but somewhat cryptic (names don't matter) code variants: {{{2{{{1|}}}|}}} {{{result{{{value|}}}|}}} {{{then{{{test|}}}|}}} Example Code Result 1 {{Ifndef/doc| |empty}} 1 2 {{Ifndef/doc|x|gotcha}} 2 3 {{Ifndef/doc| {{{1| }}} | {{{1| }}} undefined}} 3 4 {{Ifndef/doc| {{{1  }}} | {{{1  }}} bad idea}} 4 5 {{Ifndef/doc| {{ns:0}} | main namespace}} 5 6 {{Ifndef/doc||compare {{Tlx|ifdef}} }} 6 7 {{Ifndef/doc|| 2=see=[[#Caveats]] }} 7 8 {{Ifndef/doc|| see=[[#Caveats]] }} 8 Unlike ifdef the minimalistic ifndef cannot reject a missing second parameter. Caveats In templates the characters "=" (=) and "|" (|) cannot be used as is in parameters. The numeric character references = and | are often good enough, but for Wiki and XHTML markup the literal characters are required: For | template:! (edit•talk•links•history) offers a workaround. For = the template parameter mechanism allows {{ifndef}} resulting in "ok=yes" instead of {{ifndef}} resulting in "". Substitution works only for {{ifdef}}, but not for {{ifndef}} or {{qif}}.
2 {{Ifndef/doc|x|gotcha}}	2 {{ifndef/doc}} is a compact variant of {{Qif}} for simple "if defined then void else do" statements with blank then part. It's the opposite of {{ifdef}}. Usage {{Ifndef/doc|value|result}} yields result  if value  is blank. This simple template cannot be substituted, it's used to simplify the following equivalent but somewhat cryptic (names don't matter) code variants: {{{2{{{1|}}}|}}} {{{result{{{value|}}}|}}} {{{then{{{test|}}}|}}} Example Code Result 1 {{Ifndef/doc| |empty}} 1 2 {{Ifndef/doc|x|gotcha}} 2 3 {{Ifndef/doc| {{{1| }}} | {{{1| }}} undefined}} 3 4 {{Ifndef/doc| {{{1  }}} | {{{1  }}} bad idea}} 4 5 {{Ifndef/doc| {{ns:0}} | main namespace}} 5 6 {{Ifndef/doc||compare {{Tlx|ifdef}} }} 6 7 {{Ifndef/doc|| 2=see=[[#Caveats]] }} 7 8 {{Ifndef/doc|| see=[[#Caveats]] }} 8 Unlike ifdef the minimalistic ifndef cannot reject a missing second parameter. Caveats In templates the characters "=" (=) and "|" (|) cannot be used as is in parameters. The numeric character references = and | are often good enough, but for Wiki and XHTML markup the literal characters are required: For | template:! (edit•talk•links•history) offers a workaround. For = the template parameter mechanism allows {{ifndef}} resulting in "ok=yes" instead of {{ifndef}} resulting in "". Substitution works only for {{ifdef}}, but not for {{ifndef}} or {{qif}}.
3 {{Ifndef/doc| {{{1| }}} | {{{1| }}} undefined}}	3 {{ifndef/doc}} is a compact variant of {{Qif}} for simple "if defined then void else do" statements with blank then part. It's the opposite of {{ifdef}}. Usage {{Ifndef/doc|value|result}} yields result  if value  is blank. This simple template cannot be substituted, it's used to simplify the following equivalent but somewhat cryptic (names don't matter) code variants: {{{2{{{1|}}}|}}} {{{result{{{value|}}}|}}} {{{then{{{test|}}}|}}} Example Code Result 1 {{Ifndef/doc| |empty}} 1 2 {{Ifndef/doc|x|gotcha}} 2 3 {{Ifndef/doc| {{{1| }}} | {{{1| }}} undefined}} 3 4 {{Ifndef/doc| {{{1  }}} | {{{1  }}} bad idea}} 4 5 {{Ifndef/doc| {{ns:0}} | main namespace}} 5 6 {{Ifndef/doc||compare {{Tlx|ifdef}} }} 6 7 {{Ifndef/doc|| 2=see=[[#Caveats]] }} 7 8 {{Ifndef/doc|| see=[[#Caveats]] }} 8 Unlike ifdef the minimalistic ifndef cannot reject a missing second parameter. Caveats In templates the characters "=" (=) and "|" (|) cannot be used as is in parameters. The numeric character references = and | are often good enough, but for Wiki and XHTML markup the literal characters are required: For | template:! (edit•talk•links•history) offers a workaround. For = the template parameter mechanism allows {{ifndef}} resulting in "ok=yes" instead of {{ifndef}} resulting in "". Substitution works only for {{ifdef}}, but not for {{ifndef}} or {{qif}}.
4 {{Ifndef/doc| {{{1  }}} | {{{1  }}} bad idea}}	4 {{ifndef/doc}} is a compact variant of {{Qif}} for simple "if defined then void else do" statements with blank then part. It's the opposite of {{ifdef}}. Usage {{Ifndef/doc|value|result}} yields result  if value  is blank. This simple template cannot be substituted, it's used to simplify the following equivalent but somewhat cryptic (names don't matter) code variants: {{{2{{{1|}}}|}}} {{{result{{{value|}}}|}}} {{{then{{{test|}}}|}}} Example Code Result 1 {{Ifndef/doc| |empty}} 1 2 {{Ifndef/doc|x|gotcha}} 2 3 {{Ifndef/doc| {{{1| }}} | {{{1| }}} undefined}} 3 4 {{Ifndef/doc| {{{1  }}} | {{{1  }}} bad idea}} 4 5 {{Ifndef/doc| {{ns:0}} | main namespace}} 5 6 {{Ifndef/doc||compare {{Tlx|ifdef}} }} 6 7 {{Ifndef/doc|| 2=see=[[#Caveats]] }} 7 8 {{Ifndef/doc|| see=[[#Caveats]] }} 8 Unlike ifdef the minimalistic ifndef cannot reject a missing second parameter. Caveats In templates the characters "=" (=) and "|" (|) cannot be used as is in parameters. The numeric character references = and | are often good enough, but for Wiki and XHTML markup the literal characters are required: For | template:! (edit•talk•links•history) offers a workaround. For = the template parameter mechanism allows {{ifndef}} resulting in "ok=yes" instead of {{ifndef}} resulting in "". Substitution works only for {{ifdef}}, but not for {{ifndef}} or {{qif}}.
5 {{Ifndef/doc| {{ns:0}} | main namespace}}	5 {{ifndef/doc}} is a compact variant of {{Qif}} for simple "if defined then void else do" statements with blank then part. It's the opposite of {{ifdef}}. Usage {{Ifndef/doc|value|result}} yields result  if value  is blank. This simple template cannot be substituted, it's used to simplify the following equivalent but somewhat cryptic (names don't matter) code variants: {{{2{{{1|}}}|}}} {{{result{{{value|}}}|}}} {{{then{{{test|}}}|}}} Example Code Result 1 {{Ifndef/doc| |empty}} 1 2 {{Ifndef/doc|x|gotcha}} 2 3 {{Ifndef/doc| {{{1| }}} | {{{1| }}} undefined}} 3 4 {{Ifndef/doc| {{{1  }}} | {{{1  }}} bad idea}} 4 5 {{Ifndef/doc| {{ns:0}} | main namespace}} 5 6 {{Ifndef/doc||compare {{Tlx|ifdef}} }} 6 7 {{Ifndef/doc|| 2=see=[[#Caveats]] }} 7 8 {{Ifndef/doc|| see=[[#Caveats]] }} 8 Unlike ifdef the minimalistic ifndef cannot reject a missing second parameter. Caveats In templates the characters "=" (=) and "|" (|) cannot be used as is in parameters. The numeric character references = and | are often good enough, but for Wiki and XHTML markup the literal characters are required: For | template:! (edit•talk•links•history) offers a workaround. For = the template parameter mechanism allows {{ifndef}} resulting in "ok=yes" instead of {{ifndef}} resulting in "". Substitution works only for {{ifdef}}, but not for {{ifndef}} or {{qif}}.
6 {{Ifndef/doc||compare {{Tlx|ifdef}} }}	6 {{ifndef/doc}} is a compact variant of {{Qif}} for simple "if defined then void else do" statements with blank then part. It's the opposite of {{ifdef}}. Usage {{Ifndef/doc|value|result}} yields result  if value  is blank. This simple template cannot be substituted, it's used to simplify the following equivalent but somewhat cryptic (names don't matter) code variants: {{{2{{{1|}}}|}}} {{{result{{{value|}}}|}}} {{{then{{{test|}}}|}}} Example Code Result 1 {{Ifndef/doc| |empty}} 1 2 {{Ifndef/doc|x|gotcha}} 2 3 {{Ifndef/doc| {{{1| }}} | {{{1| }}} undefined}} 3 4 {{Ifndef/doc| {{{1  }}} | {{{1  }}} bad idea}} 4 5 {{Ifndef/doc| {{ns:0}} | main namespace}} 5 6 {{Ifndef/doc||compare {{Tlx|ifdef}} }} 6 7 {{Ifndef/doc|| 2=see=[[#Caveats]] }} 7 8 {{Ifndef/doc|| see=[[#Caveats]] }} 8 Unlike ifdef the minimalistic ifndef cannot reject a missing second parameter. Caveats In templates the characters "=" (=) and "|" (|) cannot be used as is in parameters. The numeric character references = and | are often good enough, but for Wiki and XHTML markup the literal characters are required: For | template:! (edit•talk•links•history) offers a workaround. For = the template parameter mechanism allows {{ifndef}} resulting in "ok=yes" instead of {{ifndef}} resulting in "". Substitution works only for {{ifdef}}, but not for {{ifndef}} or {{qif}}.
7 {{Ifndef/doc|| 2=see=[[#Caveats]] }}	7 {{ifndef/doc}} is a compact variant of {{Qif}} for simple "if defined then void else do" statements with blank then part. It's the opposite of {{ifdef}}. Usage {{Ifndef/doc|value|result}} yields result  if value  is blank. This simple template cannot be substituted, it's used to simplify the following equivalent but somewhat cryptic (names don't matter) code variants: {{{2{{{1|}}}|}}} {{{result{{{value|}}}|}}} {{{then{{{test|}}}|}}} Example Code Result 1 {{Ifndef/doc| |empty}} 1 2 {{Ifndef/doc|x|gotcha}} 2 3 {{Ifndef/doc| {{{1| }}} | {{{1| }}} undefined}} 3 4 {{Ifndef/doc| {{{1  }}} | {{{1  }}} bad idea}} 4 5 {{Ifndef/doc| {{ns:0}} | main namespace}} 5 6 {{Ifndef/doc||compare {{Tlx|ifdef}} }} 6 7 {{Ifndef/doc|| 2=see=[[#Caveats]] }} 7 8 {{Ifndef/doc|| see=[[#Caveats]] }} 8 Unlike ifdef the minimalistic ifndef cannot reject a missing second parameter. Caveats In templates the characters "=" (=) and "|" (|) cannot be used as is in parameters. The numeric character references = and | are often good enough, but for Wiki and XHTML markup the literal characters are required: For | template:! (edit•talk•links•history) offers a workaround. For = the template parameter mechanism allows {{ifndef}} resulting in "ok=yes" instead of {{ifndef}} resulting in "". Substitution works only for {{ifdef}}, but not for {{ifndef}} or {{qif}}.
8 {{Ifndef/doc|| see=[[#Caveats]] }}	8 {{ifndef/doc}} is a compact variant of {{Qif}} for simple "if defined then void else do" statements with blank then part. It's the opposite of {{ifdef}}. Usage {{Ifndef/doc|value|result}} yields result  if value  is blank. This simple template cannot be substituted, it's used to simplify the following equivalent but somewhat cryptic (names don't matter) code variants: {{{2{{{1|}}}|}}} {{{result{{{value|}}}|}}} {{{then{{{test|}}}|}}} Example Code Result 1 {{Ifndef/doc| |empty}} 1 2 {{Ifndef/doc|x|gotcha}} 2 3 {{Ifndef/doc| {{{1| }}} | {{{1| }}} undefined}} 3 4 {{Ifndef/doc| {{{1  }}} | {{{1  }}} bad idea}} 4 5 {{Ifndef/doc| {{ns:0}} | main namespace}} 5 6 {{Ifndef/doc||compare {{Tlx|ifdef}} }} 6 7 {{Ifndef/doc|| 2=see=[[#Caveats]] }} 7 8 {{Ifndef/doc|| see=[[#Caveats]] }} 8 Unlike ifdef the minimalistic ifndef cannot reject a missing second parameter. Caveats In templates the characters "=" (=) and "|" (|) cannot be used as is in parameters. The numeric character references = and | are often good enough, but for Wiki and XHTML markup the literal characters are required: For | template:! (edit•talk•links•history) offers a workaround. For = the template parameter mechanism allows {{ifndef}} resulting in "ok=yes" instead of {{ifndef}} resulting in "". Substitution works only for {{ifdef}}, but not for {{ifndef}} or {{qif}}.

Unlike ifdef the minimalistic ifndef cannot reject a missing second parameter.

Caveats

In templates the characters "=" (=) and "|" (|) cannot be used as is in parameters. The numeric character references = and | are often good enough, but for Wiki and XHTML markup the literal characters are required:

1. For | template:! (edit•talk•links•history) offers a workaround.
2. For = the template parameter mechanism allows {{ifndef}} resulting in "ok=yes" instead of {{ifndef}} resulting in "".

Substitution works only for {{ifdef}}, but not for {{ifndef}} or {{qif}}.