Method and system for providing a visual debugger for an interpreted statistical language

A non-transitory computer-readable medium whose contents enable a computing system to provide for debugging of interpreted code in a visual debugger using breakpoints that facilitate step-based evaluation of expressions, by performing a method comprising:

• presenting a user interface for receiving debugging commands;
• in response to a received debug command to set or change an indicated breakpoint in a segment of code that is expressed in an interpreted programming language and that defines one or more expressions,
• determining the nearest enclosing expression to the indicated breakpoint, including when the nearest enclosing expression begins on a line of source code associated with the code segment that is different from a line of the associated source code that contains the indicated breakpoint;
• and
• generating a breakpoint address that indicates a location in the segment of code that corresponds to the beginning of the determined enclosing expression when the code segment is evaluated;
• causing the code segment to be evaluated using an interpreter for the interpreted programming language, such that evaluation automatically stops when the location in the code segment that corresponds to the breakpoint address is encountered;
• and
• causing one or more source code statements that correspond to and indicate the location in the code segment where the evaluation stopped to be displayed in the visual interface.

A computing system for debugging code programmed in an interpreted language defining a plurality of expressions, comprising:

• a memory;
• a computer processor;
• a parser stored in the memory and configured, when executed by the computer processor, to create a parse tree for an indicated function;
• a debug command module stored in the memory and configured, when executed by the computer processor, to receive debugging commands from a user via a visual user interface and, when a command is received to set or change a breakpoint in the indicated function, generating a logical breakpoint address that indicates a nearest enclosing expression contained within the function, including when the nearest enclosing expression begins on a line of source code associated with the indicated function that is different from a line of the associated source code that contains the indicated breakpoint;
• a debug handler stored in the memory and configured, when executed by the computer processor, to receive the generated logical breakpoint address, resolve the logical breakpoint address into a memory address that corresponds to a location in the parse tree created for the function, record information to associate the breakpoint with the function;
• and
• an evaluation module for the interpreted language stored in the memory and configured, when executed by the computer processor, to receive an expression in the interpreted language that contains a call to the function, and traverse a parse tree corresponding to the received expression to generate output defined by evaluating the expression such that, when the location that corresponds to the breakpoint associated with the function is encountered in the parse tree created for the function, the evaluation module pauses to receive debug commands to further control evaluation of the expression or to examine values of objects associated with the expression.