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GEOS SDK TechDocs
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3.1 Parsing a String
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3.3 Formatting a Token Sequence
ParserEvalExpression()
To format an expression, call
ParserEvalExpression()
. This routine is passed a token sequence; it evaluates it and writes the resulting token sequence to a passed buffer. It calls a supplied callback routine to perform the following tasks:
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Return the value of a specified cell
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Return the value associated with a given identifier, specified by ID number
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Evaluate an external function, given the arguments and the function ID number
The evaluator produces a sequence two tokens long, including the "end-of-expression" token. The first token might be an error token. Two errors are so serious that if they occur, the evaluation is immediately halted and the error is returned:
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PSEE_OUT_OF_STACK_SPACE
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The evaluator ran out of stack space. Evaluation was halted when this occurred.
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PSEE_NESTING_TOO_DEEP
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The nesting grew too deep for the evaluator. Evaluation was halted when this occurred.
The following errors may be propagated; that is, if an expression returns an error, that error would be passed, as a value, to outer expressions. For example, if the evaluator were evaluating "SUM(1, (PROD(1, 2, "F. T. Poomm"))", PROD would return PSEE_WRONG_TYPE, since it expects numeric arguments. SUM, in turn, would be passed two arguments: the number 1 and the error PSEE_WRONG_TYPE. That function might, in turn, propagate the error upward, return a different error, or return a non-error value. (SUM, as it happens, would propagate the error; that is, it would return PSEE_WRONG_TYPE.)
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PSEE_ROW_OUT_OF_RANGE
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A cell's row index was out of range.
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PSEE_COLUMN_OUT_OF_RANGE
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A cell's column index was out of range.
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PSEE_FUNCTION_NO_LONGER_EXISTS
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The callback routine did not recognize the function ID for an external function.
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PSEE_BAD_ARG_COUNT
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A function was passed the wrong number of arguments.
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PSEE_WRONG_TYPE
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A function was passed an argument of the wrong type.
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PSEE_DIVIDE_BY_ZERO
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A division by zero was attempted.
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PSEE_UNDEFINED_NAME
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The callback would not provide a value for an identifier ID.
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PSEE_CIRCULAR_REF
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A circular reference occurred. This error will only occur if it is returned by the callback routine.
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PSEE_CIRCULAR_DEP
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The value is dependant on a cell whose value is PSEE_CIRCULAR_REF.
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PSEE_CIRC_NAME_REF
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The expression uses a name which is defined circularly.
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PSEE_NUMBER_OUT_OF_RANGE
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The result was a number which could not be expressed as a float.
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PSEE_GEN_ERR
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General error; this is returned when no other error code is appropriate.
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PSEE_NA
- The value for a cell was not available.
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PSEE_FLOAT_POS_INFINITY
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A float routine returned the error FLOAT_POS_INFINITY.
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PSEE_FLOAT_NEG_INFINITY
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A float routine returned the error FLOAT_NEG_INFINITY.
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PSEE_FLOAT_GEN_ERR
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A float routine returned the error FLOAT_GEN_ERR.
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PSEE_TOO_MANY_DEPENDENCIES
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The formula contained too many levels of dependency. This is generally returned by the callback routine; the Parse library routines do not return this error, they merely propagate it.
The application may also define its own error codes, beginning with the constant PSEE_FIRST_APPLICATION_ERROR. All internal functions, and all operators, always propagate application-defined errors.
| GEOS SDK TechDocs
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| 3.1 Parsing a String
| 3.3 Formatting a Token Sequence