vipsi - the friendly vip script interpreter

Appendix

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Syntax Cave-ats

Function call without parenthesis

{ .. } in the shell

log in the shell

Statements starting with '%', '-' or '+'

return and end with no return value

var argc = count globals - 1

Function call without parenthesis

With all Vipsi command syntax: Functions
Functions
Glossary: Functionfunctions which take exactly one Vipsi command syntax: Arguments
Glossary: Argumentsargument, Flow control: if … then
Flow control: try … thenthe Separators: Round brackets "( … )"
Functions with varying return types: bracket expression "()"parenthesis may be omitted, Flow control: if … then
Flow control: if … thenif the Vipsi command syntax: Arguments
Glossary: Argumentsargument is a simple Glossary: Valuevalue Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"and no Vipsi command syntax: Expressions
Glossary: Expressionexpression with Vipsi command syntax: Operators
Operators
Glossary: Operatoroperators. Flow control: if … then
Flow control: if … thenIf the Vipsi command syntax: Arguments
Glossary: Argumentsargument is a Vipsi command syntax: Expressions
Glossary: Expressionexpression, Flow control: if … then
Flow control: try … thenthen you must use Separators: Round brackets "( … )"
Functions with varying return types: bracket expression "()"parenthesis.

Numeric functions: sinsin 2*Constants: pipi   ==   Numeric functions: sinsin(2) * Constants: pipi   !=   Numeric functions: sinsin(2*Constants: pipi)

`{ .. }` in the shell

Flow control: if … then
Flow control: try … thenThe only place where List functions: thisthis may lead to confusion is Flow control: if … then
Flow control: try … thenthe vipsi shell: Operators: Make Identifier "@"At Flow control: if … then
Flow control: try … thenthe start of Flow control: if … then
Flow control: try … thenthe command line Flow control: if … then
Flow control: try … thenthe parser expects an Vipsi command syntax: Instructions
Instructions
Glossary: Instructioninstruction. For your convenience it is also possible to just type an Vipsi command syntax: Expressions
Glossary: Expressionexpression Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"and Flow control: if … then
Flow control: try … thenthe shell will print Flow control: if … then
Flow control: try … thenthe result. Thus Flow control: if … thenif you just type in

{ x=22, y=1.5, z=0 }

to see whether vipsi evaluates your Literals: List literals
Lists and arrays: List literalslist literal as expected, Flow control: if … then
Flow control: try … thenthen Flow control: if … then
Flow control: try … thenthe opening { stands Operators: Make Identifier "@"at Flow control: if … then
Flow control: try … thenthe position of an Vipsi command syntax: Instructions
Instructions
Glossary: Instructioninstruction Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"and should be handled as Flow control: if … then
Flow control: try … thenthe start of a range of Vipsi command syntax: Statements
Glossary: Statementstatements with private Glossary: Variable, var_refvariable scope.

`log` in the shell

Numeric functions: log Numeric functions: loge Instructions: loglog is used as an Vipsi command syntax: Instructions
Instructions
Glossary: Instructioninstruction which prints it's Vipsi command syntax: Arguments
Glossary: Argumentsarguments to Constants: stderrstderr Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"and as a Vipsi command syntax: Functions
Functions
Glossary: Functionfunction to calculate Flow control: if … then
Flow control: try … thenthe logarithm of any Glossary: number, num_valnumber to any Integer numbers: Base 256base. Flow control: if … then
Flow control: try … thenThe meaning depends on Flow control: if … then
Flow control: try … thenthe place where Numeric functions: log Numeric functions: loge Instructions: loglog is encountered. Flow control: if … thenIf it occurs Operators: Make Identifier "@"at Flow control: if … then
Flow control: try … thenthe place of an Vipsi command syntax: Instructions
Instructions
Glossary: Instructioninstruction Flow control: if … then
Flow control: try … thenthen it is Flow control: if … then
Flow control: try … thenthe Vipsi command syntax: Instructions
Instructions
Glossary: Instructioninstruction Numeric functions: log Numeric functions: loge Instructions: loglog which prints it Vipsi command syntax: Arguments
Glossary: Argumentsarguments to Constants: stderrstderr. Flow control: if … thenIf it occurs Operators: Make Identifier "@"at Flow control: if … then
Flow control: try … thenthe place of an Vipsi command syntax: Expressions
Glossary: Expressionexpression Flow control: if … then
Flow control: try … thenthen it is Flow control: if … then
Flow control: try … thenthe Vipsi command syntax: Functions
Functions
Glossary: Functionfunction Numeric functions: log Numeric functions: loge Instructions: loglog.

Numeric functions: log
Numeric functions: loge
Instructions: loglog(2,8)

to see what Flow control: if … then
Flow control: try … thenthe logarithm of 8 to Integer numbers: Base 256base 2 is, Flow control: if … then
Flow control: try … thenthen Flow control: if … then
Flow control: try … thenthe List functions: words
Shell Immediate Commands: wordsword Numeric functions: log Numeric functions: loge Instructions: loglog stands Operators: Make Identifier "@"at Flow control: if … then
Flow control: try … thenthe position of an Vipsi command syntax: Instructions
Instructions
Glossary: Instructioninstruction Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"and should be handled as Flow control: if … then
Flow control: try … thenthe Vipsi command syntax: Instructions
Instructions
Glossary: Instructioninstruction Numeric functions: log Numeric functions: loge Instructions: loglog.

Statements starting with '%', '-' or '+'

Flow control: if … thenIf a Vipsi command syntax: Statements
Glossary: Statementstatement after a Vipsi command syntax: Statements
Glossary: Statementstatement with Vipsi command syntax: Arguments
Glossary: Argumentsarguments starts with '-', '+' Operators: Boolean Or with Variable "||="
Operators: Bitwise Or with Variable "|="
Operators: Bitwise Or "|"
Operators: Boolean Or "||"or '%' Flow control: if … then
Flow control: try … thenthen List functions: thisthis character is Operators: Bitwise Not "~"
Operators: Boolean Negation "!"not recognized as a Glossary: number, num_valnumber Numeric functions: signsign start of a Integer numbers: Binary
Floating point: Binary
Text functions: binstrbinary Literals: Number literals
Numbers: Number literalsnumber literal but interpreted as Vipsi command syntax: Operators
Operators
Glossary: Operatoroperator Operators: Subtract "-"minus, Operators: Add "+"plus Operators: Boolean Or with Variable "||="
Operators: Bitwise Or with Variable "|="
Operators: Bitwise Or "|"
Operators: Boolean Or "||"or Operators: Remainder with Variable "%="
Operators: Remainder "%"remainder linking it to Flow control: if … then
Flow control: try … thenthe last Vipsi command syntax: Arguments
Glossary: Argumentsargument of Flow control: if … then
Flow control: try … thenthe previous Vipsi command syntax: Instructions
Instructions
Glossary: Instructioninstruction.

List functions: thisThis will almost certainly happen only in broken code.

In a sane program, each Vipsi command syntax: Statements
Glossary: Statementstatement starts with an Vipsi command syntax: Identifiers (names)
Identifiers, names
Operators: Make Identifier "@"
Glossary: Name, Identifieridentifier Vipsi command syntax: Identifiers (names)
Identifiers, names
Operators: Make Identifier "@"
Text functions: name
Glossary: Name, Identifiername:

vipsi - the friendly one.: The namethe name of a Invariants: Built-in instructionsbuilt-in instruction, like Instructions: putput
vipsi - the friendly one.: The namethe name Flow control: if … thenif a user-defined Vipsi command syntax: Procedures
Data Types: Procedures
Glossary: Procedureprocedure, like Foo
vipsi - the friendly one.: The namethe name of a Glossary: Variable, var_refvariable in an Operators: Assignment "="
Built-in operators: Assignments:assignment Vipsi command syntax: Statements
Glossary: Statementstatement, like Anton

Flow control: if … thenIf a Vipsi command syntax: Statements
Glossary: Statementstatement starts with '%', '+' Operators: Boolean Or with Variable "||="
Operators: Bitwise Or with Variable "|="
Operators: Bitwise Or "|"
Operators: Boolean Or "||"or '-', Flow control: if … then
Flow control: try … thenthen List functions: thisthis Vipsi command syntax: Expressions
Glossary: Expressionexpression will Flow control: returnreturn a result Glossary: Valuevalue. In a Example Scripts: CGI Scripts
Example Scripts: Scriptsscript List functions: thisthis result Glossary: Valuevalue will be discarded. I can hardly think of any useful code, with a Vipsi command syntax: Statements
Glossary: Statementstatement beginning with a numeric Glossary: Valuevalue. Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"And all examples i can imagine are lunatic Operators: Boolean Or with Variable "||="
Operators: Bitwise Or with Variable "|="
Operators: Bitwise Or "|"
Operators: Boolean Or "||"or malicious.

#!/usr/local/bin/vipsi
// very broken:
    +123 Instructions: var
How does VScript::Value() work?: Var*&var a=0
    -123 Instructions: var
How does VScript::Value() work?: Var*&var b=0
    +123 Instructions: var
How does VScript::Value() work?: Var*&var c=0
    %011
    Instructions: putput Constants: nlnl, "-> ", a, Constants: tabtab, b, Constants: tabtab, c, Constants: nlnl
// very insane:
    Instructions: procproc mySideEffect(a){ Instructions: putput a; Flow control: returnreturn a }
    Instructions: putput 222
    +mySideEffect(77)

Even in Flow control: if … then
Flow control: try … thenthe shell Flow control: if … thenif you want to print Flow control: if … then
Flow control: try … thenthe result of an Vipsi command syntax: Expressions
Glossary: Expressionexpression, Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"and Flow control: if … then
Flow control: try … thenthe Vipsi command syntax: Expressions
Glossary: Expressionexpression starts with a Literals: Number literals
Numbers: Number literalsnumber literal which starts with '%', '+' Operators: Boolean Or with Variable "||="
Operators: Bitwise Or with Variable "|="
Operators: Bitwise Or "|"
Operators: Boolean Or "||"or '-', List functions: thisthis is no problem, because you'll rarely append such a calculation after another Vipsi command syntax: Instructions
Instructions
Glossary: Instructioninstruction with Vipsi command syntax: Arguments
Glossary: Argumentsarguments. List functions: thisThis would look pretty insane:

vipsi> Instructions: putput 100  -123  -23
vipsi> Instructions: putput 100  +123  223
vipsi> Instructions: putput 100  %011  1
vipsi>

Flow control: if … thenIf you successfully construct a case where it matters, use Instructions: putput Operators: Boolean Or with Variable "||="
Operators: Bitwise Or with Variable "|="
Operators: Bitwise Or "|"
Operators: Boolean Or "||"or enclose it in Separators: Round brackets "( … )"
Functions with varying return types: bracket expression "()"parenthesis:

vipsi> Flow control: if … then
Flow control: if … thenif 1 -123 then /* prints nothing */
vipsi> Flow control: if … thenif 1 Instructions: putput -123 Flow control: if … then
Flow control: try … thenthen  -123
vipsi> Flow control: if … then
Flow control: if … thenif 1 (-123)   then  -123
vipsi> Flow control: if … then
Flow control: if … thenif 1; -123    then  -123
vipsi>

`return` and `end` with no return value

Instructions: putput a=22

will Operators: Assignment "="assign 22 to a Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"and print Flow control: if … then
Flow control: try … thenthe result, which is 22. Flow control: whileWhile

Instructions: putput "x" a=22

will print "x" but Operators: Bitwise Not "~"
Operators: Boolean Negation "!"not Flow control: if … then
Flow control: try … thenthe result of Flow control: if … then
Flow control: try … thenthe Operators: Assignment "="
Built-in operators: Assignments:assignment a=22, because that is a Instructions: newnew Vipsi command syntax: Instructions
Instructions
Glossary: Instructioninstruction. Flow control: if … thenIf you wanted to print both, "x" Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"and "22", Flow control: if … then
Flow control: try … thenthen you needed to append a=22 with a Separators: Comma ","comma "," to Flow control: if … then
Flow control: try … thenthe Vipsi command syntax: Arguments
Glossary: Argumentsargument Data Types: Lists and arrays
Item selector "[]": Lists
Glossary: list, list_vallist of Instructions: putput.

Additionally, Flow control: if … then
Flow control: if … thenif the Flow control: nextnext Vipsi command syntax: Instructions
Instructions
Glossary: Instructioninstruction is self-defined Vipsi command syntax: Procedures
Data Types: Procedures
Glossary: Procedureprocedure, Flow control: if … then
Flow control: try … thenthe parser Flow control: do … loopdoes Operators: Bitwise Not "~"
Operators: Boolean Negation "!"not know whether it will Flow control: returnreturn a result Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"and assume that it will. List functions: thisThis makes no difference for a Vipsi command syntax: Procedures
Data Types: Procedures
Glossary: Procedureprocedure written Operators: Make Identifier "@"at Flow control: if … then
Flow control: try … thenthe place of an Vipsi command syntax: Instructions
Instructions
Glossary: Instructioninstruction, because either it Flow control: do … loopdoes Operators: Bitwise Not "~"
Operators: Boolean Negation "!"not Flow control: returnreturn a result Operators: Boolean Or with Variable "||="
Operators: Bitwise Or with Variable "|="
Operators: Bitwise Or "|"
Operators: Boolean Or "||"or Flow control: if … then
Flow control: try … thenthe returned result will be discarded. (Operators: Bitwise Not "~"
Operators: Boolean Negation "!"note: on Flow control: if … then
Flow control: try … thenthe vipsi shell printed for your convenience.)

There is no problem. Except in one situation, which stunningly often happens to me:

When a program fails somehow Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"and i debug it, i often Instructions: putput in a Flow control: returnreturn somewhere. Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"And that position, self-evidently is Operators: Bitwise Not "~"
Operators: Boolean Negation "!"not before one of Flow control: if … then
Flow control: try … thenthe terminating Vipsi command syntax: Flow control
Flow controlflow control List functions: words
Shell Immediate Commands: wordsword. Frequently enough before a Functions with varying return types: call
Instructions: callcall to a self-defined Vipsi command syntax: Procedures
Data Types: Procedures
Glossary: Procedureprocedure Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"and Flow control: if … then
Flow control: try … thenthen Flow control: if … then
Flow control: try … thenthe Vipsi command syntax: Procedures
Data Types: Procedures
Glossary: Procedureprocedure Functions with varying return types: call
Instructions: callcall after Flow control: if … then
Flow control: try … thenthe Flow control: returnreturn unexpectedly Instructions: getgets called before Flow control: returnreturn Flow control: returnreturns, just because Flow control: if … then
Flow control: try … thenthe parser assumes that it delivers an Vipsi command syntax: Arguments
Glossary: Argumentsargument. Puzzled me sometimes.

From a real-world case:

Instructions: procproc Doit()
{
    QuelltextEinlesen()
    TagsAbtrennen()
    Flow control: returnreturn                  // <-- inserted for testing
    TagsBehandeln()
    AnkerErzeugen()
    QuerverweiseEinfügen()
    BuchNachHtmlKonvertieren()
    BuchdateienSchreiben()
}

In Flow control: if … then
Flow control: try … thenthe case above Flow control: if … then
Flow control: try … thenthe Vipsi command syntax: Procedures
Data Types: Procedures
Glossary: Procedureprocedure TagsBehandeln() was called despite Flow control: if … then
Flow control: try … thenthe Flow control: returnreturn in front of it. List functions: thisThis is, as you can see, because i never terminate my Vipsi command syntax: Instructions
Instructions
Glossary: Instructioninstructions with Separators: Semicolon ";"semicolons ";" as i should Flow control: do … loopdo. Just adding a Separators: Semicolon ";"semicolon ";" after Flow control: if … then
Flow control: try … thenthe Flow control: returnreturn did remedy Flow control: if … then
Flow control: try … thenthe problem.

var argc = count globals - 1

Ever wondered why there is 1 subtracted when storing Flow control: if … then
Flow control: try … thenthe Numeric functions: countcount of List functions: globals
Shell Immediate Commands: globalsglobal Glossary: Variable, var_refvariables into a Glossary: Variable, var_refvariable, which frequently happens to be named argc?

It's no bug, work-around Operators: Boolean Or with Variable "||="
Operators: Bitwise Or with Variable "|="
Operators: Bitwise Or "|"
Operators: Boolean Or "||"or even an ambiguity, it's just that Numeric functions: countcount List functions: globals Shell Immediate Commands: globalsglobals is executed after Instructions: var How does VScript::Value() work?: Var*&var argc, Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"and therefore Flow control: if … then
Flow control: try … thenthe Glossary: Variable, var_refvariable argc already Numeric functions: existsexists when Numeric functions: countcount Numeric functions: countcounts Flow control: if … then
Flow control: try … thenthe Glossary: number, num_valnumber of List functions: globals
Shell Immediate Commands: globalsglobal Glossary: Variable, var_refvariables. So Flow control: if … then
Flow control: try … thenthe Numeric functions: countcount will Functions with varying return types: include
Instructions: includeinclude Glossary: Variable, var_refvariable argc Operators: Boolean And with Variable "&&="
Operators: Bitwise And with Variable "&="
Operators: Bitwise And "&"
Operators: Boolean And "&&"and we Operators: Subtract from Variable "-="
Operators: Subtract "-"subtract 1 for that fact.

Just to Operators: Bitwise Not "~"
Operators: Boolean Negation "!"note it somewhere.

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