Syntax errors are reported when you click either the Check Syntax button or the Check Model button. If there is an error, it will be reported in the Errors line, and you will be positioned as near as possible to the occurrence of the error in either the Equation or Units window. If there are multiple equations, you will be positioned at the equation with the error.
Adding Variables to a Model
If you have entered any variable names that are new to a model, when you click on Check you will be asked if you want to add the variable to the model. If you have typed in the wrong name by mistake, answer no. The equation will be treated as though it had a syntax error, and you will be positioned in the Equation window at the location of the new variable. Correct the spelling and click on the Check button again. If you did intend to add a new variable, answer yes, and the processing of the equation will continue.
You cannot add a variable to a model in this manner with Vensim PLE or PLE Plus.
Changing the Input List
If you have left any variables in the input list out of the equations, or added variables that are not in the input list to the equations, you will be asked if you want to update the input list. If you answer yes, the input list will be changed, and the associated sketch, if any, updated. If you answer no, the equation will be treated as though it had a syntax error, and you can remove or add variables as appropriate.
You cannot update the input list in this manner with Vensim PLE or PLE Plus.
Ignoring Syntax Errors
If you choose to ignore a syntax error, the equation(s) for the variable will be stored literally, with the error included. Internally the equation will be kept as an A_FUNCTION_OF equation, meaning that the equation is not complete, though a list of desired inputs might be available. If the incorrect equation contains variables not on the input list, the equation will not be properly updated if you change the names of these variables. For example, if the inputs to Population are births and deaths, and you have the equation
Population = Integ(births-deaths,POPULATION_INIT + ?)
(which has an incomplete initial value), when you change the variable POPULATION INIT to POPULATION INITIAL, the equation for population will not change. If, on the other hand, you immediately correct the equation for Population and update the input list, then changes to the name of POPULATION INIT will be reflected in the equation for Population.
