Syntax

Contents:

1. Terms
2. Keywords
3. Grammar

• Calculating Point
  JReport gives Formula three chances to be executed. These chances are called Calculating Point. All those
• formulas that are By-record and is not Group-by Formula can not be calculated while Jreport engine is fetching records from data source.  This point is called while-fetching. All those formulas that are By-record and Group-by Formula can be calculated while engine is grouping records. This point is called while-grouping. All
• 
  This point is called after-grouping.
  
  
• Caller & Callee
  In the body of a formula, you can call any build-in functions or refer to the results of other formulas. This formula is Caller and the referred formula is Callee. Formula requires no recursively calling. The successive calling to the same formula will get the same result, that is

  ‘formula1 + formula1 = 2 * formula1’.

  This differs from other programming languages, such as C++ or Java.
  

• Database field variable
  This kind of variable refers to a column of a table when it appears in the parameters of a summary function, or refers to a cell of the current record when it appears in other cases.
  
  
• Data type
  Formula offers twenty-one data types. But only Number, Currency, Boolean, String, Date, Time and DateTime can be used as result data type.
  
  
• Expression
  Expression is the component of a statement.
  
  
• Global Formula
  If a formula contains or uses global variables, the formula is called Global Formula. A Global Formula can be a Summary Formula if the formula is placed in a group header or footer.
  
  
• Group-by Formula
  If the executing of a formula should be performed only after a certain grouping records, the formula is called Group-by Formula.
  
  
• Identifiers
  Identifiers are the names you supply for variables, types and functions in your formula. Identifier names only must differ in spelling from any keywords and any other Identifiers. Identifiers in formula are case insensitive.
  

• Identifier scope
  Formula names, global variables, Database fields and Parameters can be seen through all Catalogs. Others can only be seen in the body of a formula.
  
  
• Keywords
  Keywords are identifiers, which are preserved by Formula. They have special meanings to the Formula compiler.
  

• Summary & By-record Formula
  If the result of a formula is a statistics of a group, this formula is called Summary formula. It will be executed only once within its group. The other kinds of formula are called By-record Formula.
  
  
• Variable
  Variable is an identifier that refers to a storage space.
  

formula : gVarDeclStmts | statements | gVarDeclStmts ';' statements;

statements : statement | statements ';' statement;

gVarDeclStmts : gVarDeclStmt | gVarDeclStmts ';' gVarDeclStmt;

gVarDeclStmt : TKGLOBAL basictype typedescriptor gvarlist;

gvarlist : gvar | gvarlist ',' gvar;

gvar : TKNAME | TKNAME '=' expression | TKNAME '[' arraysize ']' | TKNAME '[' arraysize ']' '=' expression;

statement : emptystmt | exprstmt | lVarDeclStmt | ifelsestmt | returnstmt | compoundstmt;

ifelsestmt : ifpart elsepart;

ifpart : TKIF '(' expression ')' then statement;

then : | TKTHEN;

elsepart : | TKELSE statement;

compoundstmt : '{' statementlist '}' ;

statementlist : statement | statementlist ';' statement;

returnstmt : TKRETURN expression;

emptystmt : exprstmt : expression;

lVarDeclStmt : basictype typedescriptor lvarlist;

lvarlist : lvar | lvarlist ',' lvar;

lvar : TKNAME | TKNAME '=' expression | TKNAME '[' arraysize ']' | TKNAME '[' arraysize ']' '=' expression;

arraysize : | expression;

basictype : TKNUMBER | TKCURRENCY | TKSTRING | TKBOOLEAN | TKDATE | TKTIME | TKTIMESTAMP;

typedescriptor : | TKRANGE;

expression  : TKCONSTFLOAT | TKCONSTSTRING | TKTRUE | TKFALSE | '(' expression ')' | expression '+' expression | expression '-' expression | expression '*' expression | expression '/' expression | expression '%' expression | expression TKOR expression | expression TKAND expression | '!'expression | expression '<' expression | expression '>' expression | expression TKGE expression // >= | expression TKLE expression // <= | expression TKEQ expression // == | expression TKUNEQ expression // <> != | expression TKIN expression | '-' expression %prec UMINUS | '$' expression | function | variable // variable or global variable | SpecialVariable | expression '['subscriptexpr ']' | '[' expression arrayrange ']' | variable '=' expression;

subscriptexpr : expression | subrange //expression TKTO expression;

arrayrange : array | range;

array   : | ',' arrayelements;

arrayelements : expression | arrayelements ',' expression;

range : TKTO expression;

subrange : expression TKTO expression;

variable : TKNAME;

function : funcname '(' paramlist ')';

funcname : TKNAME;

paramlist : | expression | paramlist ',' expression;

SpecialVariable : '@' spvarname;

spvarname : TKNAME | TKCONSTSTRING;