The TASM Language Reference Manual Version 1.1 - Synrc

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– CV is the set of Controlled Variables = {cv | cv ∈ EV and cv is read-write in R} – IV is the set of Internal Variables = {(it, iv) | iv is a unique name and it ∈ T U is its type } – R is the set of Rules = {(n, r) | n is a name and r is a rule of the form ”if C then A” where C is an expression that evaluates to an element in BV U and A is an action} An action A is a sequence of one or more updates to environment variables, of the form v := vu where v ∈ CV and vu is an expression that evaluates to an element in the type of v. Updates to environment variables are organized in steps, where each step corresponds to a single rule application. A rule is enabled if its guarding condition, C, evaluates to the boolean value T rue. A restriction on the set of rules is that they are mutually exclusive, that is, only one rule can be enabled before each step. The update set for the i th step (i ¿ 0), denoted U i , is defined as the collection of all updates to controlled variables for the step. An update set U i will contain 0 or more pairs (cv, v) of assignments of values to controlled variables. An update set is said to be consistent if there are no conflicting updates in the set, that is, no variable is updated twice with different values. That is, an update set U is consistent if: • For all two update pairs (cv1, v1), (cv2, v2) in U if cv1 = cv2 then v1 = v2 A run of a basic ASM is defined by a sequence, potentially infinite, of update sets. For an ASM that terminates after n steps, a run would look like: U 1 , U 2 , . . . , U n The state progression can be obtained by applying the update set at each step. For an ASM that terminates after n steps, the state progression would look like: S 0 , S 1 , S 2 , . . . , S n The state S 0 denotes the initial values of the environment at the beginning of the machine execution. We introduce the ◦ operator to denote the application of the an update set to the current state to yield a new state. More specifically: S i = S i−1 ◦ U i (i > 0) We differentiate between external and internal state. The external state is the set of all environment variables. A specific instance of the state is a snapshot of the dynamics at a fixed point in time (defined as a specific step of the machine). The internal state is the set of all internal variables, not visible to the environment. We use these different concepts of state to differentiate between observable and unobservable behavior. The basic concepts explained so far are illustrated in TASM Example 1 which lists the basic logic for a light controller that monitors the status of a switch and turns a light On/Off depending on the status of the switch. 10
TASM Example 1 Light Switch Version 1 ENVIRONMENT: USER-DEFINED TYPES: light_status := {ON, OFF}; switch_status := {UP, DOWN}; VARIABLES: light_status light := OFF; switch_status switch := DOWN; -------------------------------- MAIN MACHINE: MONITORED VARIABLES: switch; CONTROLLED VARIABLES: light; INTERNAL VARIABLES: RULES: R1: Turn On if light = OFF and switch = UP then light := ON; R2: Turn Off if light = ON and switch = DOWN then light := OFF; 11
Page 1 and 2: The TASM Language Reference Manual
Page 3 and 4: Contents 1 Introduction 5 2 The Lan
Page 5 and 6: List of Figures 2.1 Hierarchical co
Page 7 and 8: Chapter 1 Introduction This documen
Page 9 and 10: Chapter 2 The Language The Timed Ab
Page 11: 2.2 Basic Definitions The term spec
Page 15 and 16: The keyword next, used with time sp
Page 17 and 18: of resource usage for the step. If
Page 19 and 20: • T RU 1 = (5, ((memory, 200), (p
Page 21 and 22: The composition of resources also f
Page 23 and 24: T RU ret = T RU 1 ⊕ ( (T RU 2 ⊕
Page 25 and 26: • T RS 0 = (0, ((memory, 0)), ((l
Page 27 and 28: RC 1 ⊙ RC 2 = (rc 11 , . . . , rc
Page 29 and 30: The example is further extended to
Page 31 and 32: TASM Example 8 Fan Main Machine Def
Page 33 and 34: Table 2.1: Special Operators Operat
Page 35 and 36: main machine templates. The concept
Page 37 and 38: Chapter 3 Syntax This chapter descr
Page 39 and 40: Table 3.1: Reserved Keywords Keywor
Page 41 and 42: Table 3.2: Operators Operator Signa
Page 43 and 44: TASMUCaseLetter > ::= ′ A ′ |
Page 45 and 46: 3.2.2 Project < TASMProjectDef > ::
Page 47 and 48: 3.2.5 Syntax Common to all Machine
Page 49 and 50: 3.2.8 Function Machine < TASMFTempl
Page 51 and 52: Table 3.3: XML Tags for Top Level S
Page 53 and 54: env types rsrcs vars vname tname *
Page 55 and 56: sys confs * conf name desc viname v
Page 57 and 58: XML Example 4 XML for a list of tem
Page 59 and 60: cons cbody cparams body * cparam cp
Page 61 and 62: XML Example 5 XML for main ASM temp
Page 63 and 64:
Table 3.11: XML Syntax Tree for Fun
Page 65 and 66:
3.4.2 Typing All variables are stat
Page 67 and 68:
Table 4.1: Operator Precedence Oper
Page 69 and 70:
4.2.5 Rules The desugaring of the r
Page 71 and 72:
is used to sum up all of the resour
Page 73:
[10] Y. Gurevich. Evolving Algebras
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